diff --git a/apps/payment/models.py b/apps/payment/models.py
index 5ec8e1ac..d3b42c8c 100644
--- a/apps/payment/models.py
+++ b/apps/payment/models.py
@@ -157,7 +157,7 @@ class SchoolPayment(Payment):
             models.Sum('month_price'),
         )
         month_price_sum = aggregate.get('month_price__sum', 0)
-        if len(self.weekdays) > 7:
+        if month_price_sum > config.SERVICE_DISCOUNT_MIN_AMOUNT:
             discount = config.SERVICE_DISCOUNT
         else:
             discount = 0