diff --git a/WebApi_data_value/Services/BackgroundService.cs b/WebApi_data_value/Services/BackgroundService.cs
index 16bf616..d9ba3be 100644
--- a/WebApi_data_value/Services/BackgroundService.cs
+++ b/WebApi_data_value/Services/BackgroundService.cs
@@ -39,7 +39,7 @@ public class ParkingService : BackgroundService
             var _context = scope.ServiceProvider.GetRequiredService<SqlContext>();
 
             var now = DateTime.Now;
-            var startTime = now.AddHours(-12);   // 獲取最近 12 小時進入的車輛
+            var startTime = now.AddHours(-15);   // 獲取最近 15 小時進入的車輛
             var inCars = await _context.yuntech_in_car_table
                 .Where(car => car.in_time >= startTime)
                 .ToListAsync(stoppingToken);
@@ -70,9 +70,21 @@ public class ParkingService : BackgroundService
                 }
                 else
                 {
-                    temporarycar++;
+                 
+                    if (temporarycar % 2 == 1)
+                    {
+                        temporarycar++; 
+                    }
+                    else
+                    {
+                        temporarycar--;
+                    }
                 }
             }
+            //絕對值
+            monthlycar = Math.Abs(monthlycar);
+            temporarycar = Math.Abs(temporarycar); 
+
             _logger.LogInformation($"月租車位數量: {monthlycar}");
             _logger.LogInformation($"臨停車位數量: {temporarycar}");