diff --git a/src/main/java/com/interplug/qcast/biz/estimate/EstimateService.java b/src/main/java/com/interplug/qcast/biz/estimate/EstimateService.java
index 762dd534..cc870e12 100644
--- a/src/main/java/com/interplug/qcast/biz/estimate/EstimateService.java
+++ b/src/main/java/com/interplug/qcast/biz/estimate/EstimateService.java
@@ -1824,6 +1824,10 @@ public class EstimateService {
         byte[] excelBytes =
                 excelUtil.download(request, response, excelData, excelList, excelTemplateNam);
 
+        if (excelBytes == null || excelBytes.length == 0) {
+          throw new RuntimeException("Excel template processing returned empty result. Template: " + excelTemplateNam);
+        }
+
         InputStream in = new ByteArrayInputStream(excelBytes);
         workbook = WorkbookFactory.create(in); // JXLS POI 엑셀로 재변환
 
diff --git a/src/main/java/com/interplug/qcast/util/ExcelUtil.java b/src/main/java/com/interplug/qcast/util/ExcelUtil.java
index a725d097..44925563 100644
--- a/src/main/java/com/interplug/qcast/util/ExcelUtil.java
+++ b/src/main/java/com/interplug/qcast/util/ExcelUtil.java
@@ -69,7 +69,8 @@ public class ExcelUtil {
         excelBytes = byteArrayOutputStream.toByteArray();
       }
     } catch (Exception e) {
-      log.debug(e.getMessage());
+      log.error("ExcelUtil.download error: {}", e.getMessage(), e);
+      throw new RuntimeException("Excel template processing failed", e);
     }
 
     return excelBytes;
@@ -118,7 +119,8 @@ public class ExcelUtil {
         JxlsHelper.getInstance().processTemplate(is, os, context);
       }
     } catch (Exception e) {
-      log.debug(e.getMessage());
+      log.error("ExcelUtil.download error: {}", e.getMessage(), e);
+      throw new RuntimeException("Excel template processing failed", e);
     }
   }
 
diff --git a/src/main/resources/mappers/estimate/estimateMapper.xml b/src/main/resources/mappers/estimate/estimateMapper.xml
index fb721f5c..0ab01ebd 100644
--- a/src/main/resources/mappers/estimate/estimateMapper.xml
+++ b/src/main/resources/mappers/estimate/estimateMapper.xml
@@ -396,116 +396,76 @@
     <select id="selectEstimateRoofCertVolKw" parameterType="com.interplug.qcast.biz.estimate.dto.EstimateRequest" resultType="String">
         /* sqlid : com.interplug.qcast.biz.estimate.selectEstimateRoofCertVolKw */
       <![CDATA[
-        SELECT
-            CAST(
-                    SUM(
-                            CASE
-                                WHEN (X.M_VOL_KW + X.M_VOL_KW2) < X.PC_VOL_KW THEN (X.M_VOL_KW + X.M_VOL_KW2)
-                                WHEN X.PC_VOL_KW <= (X.M_VOL_KW + X.M_VOL_KW2) THEN X.PC_VOL_KW
-                                ELSE 0
-                                END
-                    ) AS DECIMAL(18,3)
-            ) AS CERT_VOL_KW
-        FROM (
-                 SELECT DISTINCT
-                     Y.M_ITEM_ID,
-                     Y.M_SPEC,
-                     (Y.M_AMT2 - Y.M_AMT) AS M_CNT,
-                     ROUND((Y.M_AMT  * CAST(ISNULL(Y.M_SPEC, 0) AS FLOAT) / 1000), 4) AS M_VOL,
-                     ROUND((Y.M_AMT2 * CAST(ISNULL(Y.M_SPEC, 0) AS FLOAT) / 1000), 4) AS M_VOL2,
-                     ROUND(((Y.M_AMT2 - Y.M_AMT) * CAST(ISNULL(Y.M_SPEC, 0) AS FLOAT) / 1000), 4) AS R_VOL,
-                     CASE
-                         WHEN Y.M_AMT < Y.M_AMT2
-                             THEN ROUND((Y.M_AMT * CAST(ISNULL(Y.M_SPEC, 0) AS FLOAT) / 1000), 4)
-                         ELSE
-                             ROUND((Y.M_AMT2 * CAST(ISNULL(Y.M_SPEC, 0) AS FLOAT) / 1000), 4)
-                         END AS M_VOL_KW,
-                     ROUND((Y.P_AMT * CAST(ISNULL(Y.P_SPEC, 0) AS FLOAT) / 1000), 4) AS PC_VOL_KW,
-                     CASE
-                         WHEN 0 < (Y.M_AMT2 - Y.M_AMT)
-                             THEN ROUND(((Y.M_AMT2 - Y.M_AMT) * CAST(ISNULL(Y.M_SPEC2, 0) AS FLOAT) / 1000), 4)
-                         ELSE 0
-                         END AS M_VOL_KW2
-                 FROM (
-                          SELECT
-                              ZC.ROOF_ITEM_NO,
-                              ZC.M_ITEM_ID,
-                              ZC.M_SPEC,
-                              ZC.M_AMT,
-                              (ZC.M_1 + ZC.M_2 + ZC.M_3) AS M_AMT2,
-                              ZC.P_ITEM_ID,
-                              ZC.P_AMT,
-                              ZC.PC_ITEM_ID,
-                              ZC.QCAST_CUST_PRD_ID,
-                              CASE
-                                  WHEN ZC.P_SPEC != '0' THEN P_SPEC
-                                  WHEN ZC.CUST_SPEC != '0' THEN CUST_SPEC
-                                  WHEN ZC.PC_SPEC != '0' THEN PC_SPEC
-                                  ELSE '0'
-                                  END AS P_SPEC,
-                              (SELECT SPECIFICATION
-                               FROM T_PART_ROOF_ITEM_ESTIMATE
-                               WHERE OBJECT_NO = ZC.OBJECT_NO
-                                 AND PLAN_NO = ZC.PLAN_NO
-                                 AND ROOF_ITEM_NO = (ZC.ROOF_ITEM_NO + 1)) AS M_SPEC2
-                          FROM (
-                                   SELECT
-                                       Z.*,
-                                       CAST(ISNULL(SPLIT.M_1, 0) AS INT) AS M_1,
-                                       CAST(ISNULL(SPLIT.M_2, 0) AS INT) AS M_2,
-                                       CAST(ISNULL(SPLIT.M_3, 0) AS INT) AS M_3
-                                   FROM (
-                                            SELECT
-                                                TRI.ROOF_ITEM_NO,
-                                                TRI.OBJECT_NO,
-                                                TRI.PLAN_NO,
-                                                TRI.ITEM_ID AS M_ITEM_ID,
-                                                TRI.ITEM_NO,
-                                                TRI.SPECIFICATION AS M_SPEC,
-                                                TRI.AMOUNT AS M_AMT,
-                                                TCI.ITEM_ID AS P_ITEM_ID,
-                                                TRI.PC_ITEM_ID,
-                                                TRI.QCAST_CUST_PRD_ID,
-                                                TCI.P_AMT,
-                                                (SELECT ISNULL(M.PNOW_W,0) FROM M_ITEM M WHERE M.ITEM_ID  = TCI.ITEM_ID) AS P_SPEC,
-                                                (SELECT ISNULL(M.PNOW_W,0) FROM M_ITEM M WHERE M.ITEM_ID = TRI.PC_ITEM_ID) AS PC_SPEC,
-                                                (SELECT ISNULL(M.PNOW_W,0) FROM M_ITEM M WHERE M.ITEM_ID = TRI.QCAST_CUST_PRD_ID) AS CUST_SPEC,
-                                                TCI.CIRCUIT_CFG
-                                            FROM T_PART_ROOF_ITEM_ESTIMATE TRI
-                                                     INNER JOIN (
-                                                SELECT
-                                                    TI.CIRCUIT_NO,
-                                                    TI.OBJECT_NO,
-                                                    TI.PLAN_NO,
-                                                    TI.ITEM_ID,
-                                                    TI.CIRCUIT_CFG,
-                                                    COUNT(*) AS P_AMT
-                                                FROM T_PART_CIRCUIT_ITEM_ESTIMATE TI
-                                                GROUP BY TI.CIRCUIT_NO, TI.OBJECT_NO, TI.PLAN_NO, TI.ITEM_ID, TI.CIRCUIT_CFG
-                                            ) TCI
-                                                                ON TRI.ROOF_ITEM_NO = TCI.CIRCUIT_NO
-                                                                    AND TRI.OBJECT_NO = TCI.OBJECT_NO
-                                                                    AND TRI.PLAN_NO  = TCI.PLAN_NO
-                                            WHERE
-                                                TRI.OBJECT_NO = #{objectNo}
-                                              AND TRI.PLAN_NO  = #{planNo}
-                                        ) Z
-                                       CROSS APPLY (
-                SELECT
-                    X.value('(/x[1]/v[1])[1]', 'VARCHAR(50)') AS M_1,
-                    X.value('(/x[1]/v[2])[1]', 'VARCHAR(50)') AS M_2,
-                    X.value('(/x[1]/v[3])[1]', 'VARCHAR(50)') AS M_3
-                FROM (
-                    SELECT CAST('<x><v>' + REPLACE(ISNULL(Z.CIRCUIT_CFG, ''), ',', '</v><v>') + '</v></x>' AS XML)
-                ) A(X)
-            ) SPLIT
-                               ) ZC
-                                   INNER JOIN T_PART_ESTIMATE TE
-                                              ON ZC.OBJECT_NO = TE.OBJECT_NO
-                                                  AND ZC.PLAN_NO  = TE.PLAN_NO
-                                                  AND TE.ITEM_ID IN (ZC.P_ITEM_ID, ZC.PC_ITEM_ID, ZC.QCAST_CUST_PRD_ID)
-                      ) Y
-             ) X
+        ;WITH
+        CS AS (
+            SELECT
+                cie.CIRCUIT_NO, cie.OBJECT_NO, cie.PLAN_NO,
+                cie.ITEM_ID AS CIRCUIT_ITEM_ID, cie.CIRCUIT_CFG,
+                (SELECT SUM(CAST(LTRIM(RTRIM(x.X.value('.','VARCHAR(10)'))) AS INT))
+                 FROM (SELECT CAST('<X>'+REPLACE(cie.CIRCUIT_CFG,',','</X><X>')+'</X>' AS XML) AS d) t
+                     CROSS APPLY t.d.nodes('/X') AS x(X)
+                     ) AS CIRCUIT_SUM
+                 FROM T_PART_CIRCUIT_ITEM_ESTIMATE cie
+                 WHERE cie.OBJECT_NO = #{objectNo} AND cie.PLAN_NO = #{planNo}
+                   AND cie.CIRCUIT_CFG IS NOT NULL
+                     ),
+                     CC AS (
+                 SELECT cs.*,
+                     ISNULL((SELECT SUM(c2.CIRCUIT_SUM) FROM CS c2
+                     WHERE c2.OBJECT_NO=cs.OBJECT_NO AND c2.PLAN_NO=cs.PLAN_NO
+                     AND c2.CIRCUIT_NO < cs.CIRCUIT_NO), 0) AS CUM_START,
+                     ISNULL((SELECT SUM(c2.CIRCUIT_SUM) FROM CS c2
+                     WHERE c2.OBJECT_NO=cs.OBJECT_NO AND c2.PLAN_NO=cs.PLAN_NO
+                     AND c2.CIRCUIT_NO <= cs.CIRCUIT_NO), 0) AS CUM_END
+                 FROM CS cs
+                     ),
+                     RC AS (
+                 SELECT
+                     rie.ROOF_ITEM_NO, rie.ROOF_SURFACE_ID, rie.OBJECT_NO, rie.PLAN_NO,
+                     rie.ITEM_ID AS ROOF_ITEM_ID, rie.ITEM_NAME,
+                     CAST(rie.SPECIFICATION AS FLOAT) AS SPEC, rie.AMOUNT, rie.PC_ITEM_ID,
+                     ISNULL((SELECT SUM(r2.AMOUNT) FROM T_PART_ROOF_ITEM_ESTIMATE r2
+                     WHERE r2.OBJECT_NO=rie.OBJECT_NO AND r2.PLAN_NO=rie.PLAN_NO
+                     AND r2.ROOF_SURFACE_ID=rie.ROOF_SURFACE_ID
+                     AND r2.ROOF_ITEM_NO < rie.ROOF_ITEM_NO), 0) AS CUM_START,
+                     ISNULL((SELECT SUM(r2.AMOUNT) FROM T_PART_ROOF_ITEM_ESTIMATE r2
+                     WHERE r2.OBJECT_NO=rie.OBJECT_NO AND r2.PLAN_NO=rie.PLAN_NO
+                     AND r2.ROOF_SURFACE_ID=rie.ROOF_SURFACE_ID
+                     AND r2.ROOF_ITEM_NO <= rie.ROOF_ITEM_NO), 0) AS CUM_END
+                 FROM T_PART_ROOF_ITEM_ESTIMATE rie
+                 WHERE rie.OBJECT_NO = #{objectNo} AND rie.PLAN_NO = #{planNo}
+                     ),
+                     ALLOC AS (
+                 SELECT
+                     cc.CIRCUIT_NO, cc.CIRCUIT_ITEM_ID, cc.CIRCUIT_CFG, cc.CIRCUIT_SUM,
+                     rc.ROOF_ITEM_NO, rc.ROOF_ITEM_ID, rc.SPEC, rc.PC_ITEM_ID,
+                     -- 할당량 = MIN(끝,끝) - MAX(시작,시작)
+                     CASE WHEN cc.CUM_END < rc.CUM_END THEN cc.CUM_END ELSE rc.CUM_END END
+                     - CASE WHEN cc.CUM_START > rc.CUM_START THEN cc.CUM_START ELSE rc.CUM_START END AS ALLOCATED_QTY
+                 FROM CC cc
+                     INNER JOIN RC rc ON cc.OBJECT_NO = rc.OBJECT_NO AND cc.PLAN_NO = rc.PLAN_NO
+                 WHERE cc.CUM_START < rc.CUM_END AND cc.CUM_END > rc.CUM_START
+                     ),
+                     DETAIL AS (
+                 SELECT
+                     a.CIRCUIT_NO, a.CIRCUIT_ITEM_ID, a.CIRCUIT_CFG, a.CIRCUIT_SUM,
+                     a.ROOF_ITEM_NO, a.ROOF_ITEM_ID, a.ALLOCATED_QTY,
+                     ROUND(a.SPEC, 3) * a.ALLOCATED_QTY AS SPEC_X_QTY,
+                     (SELECT mi.PNOW_W FROM M_ITEM mi WHERE mi.ITEM_ID = a.CIRCUIT_ITEM_ID) AS PNOW_W
+                 FROM ALLOC a
+                     ),
+                     CIRCUIT_AGG AS (
+                 SELECT
+                     CIRCUIT_NO, CIRCUIT_ITEM_ID, CIRCUIT_CFG, CIRCUIT_SUM,
+                     SUM(SPEC_X_QTY) AS SUM_SPEC_X_QTY, PNOW_W,
+                     CASE WHEN SUM(SPEC_X_QTY) <= PNOW_W THEN SUM(SPEC_X_QTY) ELSE PNOW_W END AS MIN_VALUE
+                 FROM DETAIL
+                 GROUP BY CIRCUIT_NO, CIRCUIT_ITEM_ID, CIRCUIT_CFG, CIRCUIT_SUM, PNOW_W
+                     )
+
+                SELECT ROUND((SUM(MIN_VALUE) / 1000), 4)  AS CERT_VOL_KW
+                FROM CIRCUIT_AGG
+
         ]]>
 
     </select>