diff --git a/src/lib/utils.ts b/src/lib/utils.ts
index 58a452f..c6e22d3 100644
--- a/src/lib/utils.ts
+++ b/src/lib/utils.ts
@@ -251,7 +251,12 @@ export function getModelUsageSummary(data: CopilotUsageData[]): ModelUsageSummar
     }
     
     // Calculate excess cost
-    groupedSummary[key].excessCost = groupedSummary[key].exceedingRequests * groupedSummary[key].multiplier * EXCESS_REQUEST_COST;
+    // Free models (multiplier = 0) have no excess cost
+    if (groupedSummary[key].multiplier === 0) {
+      groupedSummary[key].excessCost = 0;
+    } else {
+      groupedSummary[key].excessCost = groupedSummary[key].exceedingRequests * EXCESS_REQUEST_COST;
+    }
   });
   
   // Convert to array and sort by total requests (descending)
@@ -396,7 +401,7 @@ export const MODEL_MULTIPLIERS: Record<string, number> = {
 };
 
 // Default models that should be grouped
-export const DEFAULT_MODELS = ['GPT-4o', 'GPT-4.1', 'gpt-4o-2024-11-20', 'gpt-4.1-2025-04-14'];
+export const DEFAULT_MODELS = ['GPT-4o', 'GPT-4.1', 'GPT-5 mini', 'gpt-4o-2024-11-20', 'gpt-4.1-2025-04-14'];
 
 function normalizeModelName(model: string): string {
   return model.replace(/^Auto:\s*/, '').trim();
@@ -952,13 +957,13 @@ export function getExpectedExcessCost(data: CopilotUsageData[], plan: string = C
 
     const numDays = datesForAverage.length;
 
-    // Project extra requests per model over remaining days and apply cost multiplier
+    // Project extra requests per model over remaining days
     Object.entries(modelTotals).forEach(([model, total]) => {
       const multiplier = getModelMultiplier(model);
       if (multiplier === 0) return; // Free models have no cost
       const dailyAvg = total / numDays;
       const projectedExtra = dailyAvg * remainingDays;
-      totalExpectedCost += projectedExtra * multiplier * EXCESS_REQUEST_COST;
+      totalExpectedCost += projectedExtra * EXCESS_REQUEST_COST;
     });
   });
 
diff --git a/src/test/model-info-limits.test.ts b/src/test/model-info-limits.test.ts
index a5cf9f7..3656811 100644
--- a/src/test/model-info-limits.test.ts
+++ b/src/test/model-info-limits.test.ts
@@ -98,14 +98,15 @@ describe('Model Info and Limits Feature', () => {
     expect(defaultGroup).toBeDefined();
     
     if (defaultGroup) {
-      // 50 exceeding requests * 0x multiplier * $0.04 = $0.00
-      expect(defaultGroup.excessCost).toBe(50 * 0 * EXCESS_REQUEST_COST);
+      // Default models are free (multiplier = 0), so excess cost is always $0.00
+      // even if there are exceeding requests
+      expect(defaultGroup.excessCost).toBe(0);
     }
-    
+
     const o3Model = result.find(item => item.model === 'o3-mini-2025-01-31');
     if (o3Model) {
-      // 10 exceeding requests * 0.33x multiplier * $0.04 = $0.132
-      expect(o3Model.excessCost).toBe(10 * 0.33 * EXCESS_REQUEST_COST);
+      // 10 exceeding requests * $0.04 = $0.40
+      expect(o3Model.excessCost).toBe(10 * EXCESS_REQUEST_COST);
     }
   });