Hi, i don't know if it's a bug or it's the right section to post this problem. so i've ZC 1.3.8a. i've 3 discount group (25, 35, 45%) and everything seems ok until the checkout when ZC calculates the group discount on shipping also... I tried to solve this problem by myself looking on few ZC support sites but someone said that it depends how ZC calculate taxes applying discount not on the subtotal and then adding shipping but applying the discount to (subtotal + shipping) and then taxes. Note: i cant upgrade to 1.3.9 because i've a template by templatemoster verified for 1.3.8. thank Alessandro