diff --git a/server/ptc_api_server.py b/server/ptc_api_server.py
index 7fc4df5..8f2a202 100644
--- a/server/ptc_api_server.py
+++ b/server/ptc_api_server.py
@@ -1148,7 +1148,7 @@ def build_project_lifecycle_cost(
 
     rows.sort(key=lambda item: (role_order.index(item["project_type"]), item["project_code"]))
     total_income = sum(float(item.get("income_supply") or 0) for item in rows_with_allocation)
-    total_expense = sum(float(item.get("adjusted_expense_supply") or 0) for item in rows_with_allocation)
+    total_expense = sum(float(item.get("expense_supply") or 0) for item in rows_with_allocation)
     project_codes = [item.get("project_code") for item in rows_with_allocation if item.get("project_code")]
     breakdown_components = {
         "시공비": {"direct": 0.0, "shared": 0.0, "total": 0.0},
@@ -1202,13 +1202,19 @@ def build_project_lifecycle_cost(
             numerator = int(project_info.get("allocation_numerator") or 1)
             denominator = int(project_info.get("allocation_denominator") or 1)
             allocation_ratio = float(project_info.get("allocation_ratio") or 1.0)
-            expense_supply = float(row["expense_supply"] or 0) * allocation_ratio
+            base_expense_supply = float(row["expense_supply"] or 0)
 
-            # Until common-cost allocation is introduced, lifecycle-linked costs
-            # are treated as direct costs for the target project.
-            source_component = "direct"
-            breakdown_components[bucket][source_component] += expense_supply
-            breakdown_components[bucket]["total"] += expense_supply
+            # 영업/설계는 배분 비율이 직접분이며, 미배분 잔액은 공통배분분으로 분리한다.
+            if project_type in {"영업", "설계"}:
+                direct_expense_supply = base_expense_supply * allocation_ratio
+                shared_expense_supply = max(base_expense_supply - direct_expense_supply, 0.0)
+            else:
+                direct_expense_supply = base_expense_supply
+                shared_expense_supply = 0.0
+
+            breakdown_components[bucket]["direct"] += direct_expense_supply
+            breakdown_components[bucket]["shared"] += shared_expense_supply
+            breakdown_components[bucket]["total"] += base_expense_supply
 
             project_entry = breakdown_project_maps[bucket].setdefault(
                 project_code,
@@ -1226,8 +1232,9 @@ def build_project_lifecycle_cost(
                     "expense_supply": 0.0,
                 },
             )
-            project_entry[f"{source_component}_expense_supply"] += expense_supply
-            project_entry["expense_supply"] += expense_supply
+            project_entry["direct_expense_supply"] += direct_expense_supply
+            project_entry["shared_expense_supply"] += shared_expense_supply
+            project_entry["expense_supply"] += base_expense_supply
 
             account_entry = breakdown_account_maps[bucket].setdefault(
                 account_code or "미지정",
@@ -1239,8 +1246,9 @@ def build_project_lifecycle_cost(
                     "expense_supply": 0.0,
                 },
             )
-            account_entry[f"{source_component}_expense_supply"] += expense_supply
-            account_entry["expense_supply"] += expense_supply
+            account_entry["direct_expense_supply"] += direct_expense_supply
+            account_entry["shared_expense_supply"] += shared_expense_supply
+            account_entry["expense_supply"] += base_expense_supply
 
     breakdown = [
         {