Coupon discount calculation on subtotal

Hi There,

I have a issue to find out.

I use the coupon add-on from Gravity Forms. This works fine, but i need the calculation on the subtotal field, not on the total field.

I use a coupon from 5% procent discount. I need that calculation on the subtotal, because i have a deposit calculation after the subtotal field.

I hope someone can helpt me with this issue.