Customers % dosent change at all

[urbach 0]

I really dont know which version I have installed. But I can only give my customers 10% discount coupon in the "coupon admin" if I change it the coupon to 15% it only gives the customer 10%. I can change the % to anything I want and it only give 10% discount. Is there any fix for this problem or update I should do?

 

Thanks

Steven