diff --git a/pricing/pricing.py b/pricing/pricing.py
index 0188bee..1cccd30 100644
--- a/pricing/pricing.py
+++ b/pricing/pricing.py
@@ -483,10 +483,11 @@ class PricingProgram:
 	async def buffered_charging(ppid, data):
 		r = await PricingProgram.get_ppid_pricing(ppid)
 		prices = PricingProgram.get_pricing_from_ymalstr(data,
-					r.pricing_data)
+				r.pricing_data)
 		amt = 0.0
+		discount = max(0.0, min(1.0, r.discount)) if r.discount is not None else 1.0
 		for p in prices:
-			p.cost = p.amount * r.discount
+			p.cost = p.amount * discount
 		return prices
 
 	async def charging(sor, ppid, data):
@@ -518,8 +519,9 @@ order by b.enabled_date desc"""
 					r.pricing_data)
 			debug(f'{r.prices=}')
 			amt = 0.0
+			discount = max(0.0, min(1.0, r.discount)) if r.discount is not None else 1.0
 			for p in r.prices:
-				p.cost = p.amount * r.discount
+				p.cost = p.amount * discount
 			return r.prices
 
 	@staticmethod