Gift Certificate make a strange count

This is the problem.....

Product: €11
Shipping cost: €6.89

Gift Certificate: 50 euro
---------------------------------------
At the checkout.....

Product: €11,00
Sub: €11,00
Shipping: €13,78 ->WHY??? (must be 6.89€)
Coupon: - €17,89 -> WHY??? (must be -11.00€ or -(11.00+Shipping cost)

Tot: €6,89 (must be 0€ or only shipping cost)

I've the AWOCoupon PRO 1.5.3 with VM1

Thank You

Hello,

Yes, definitely problem with 1.5.3. Please upgrade to the latest, 1.5.4, this issue has been fixed:
https://awodev.com/documentation/frequently-asked-questions#install-upgrade