Magento discount wrong with amasty promotion module.

I use the amasty promotion module to give the cheapest product for free when they buy 4 products. This works. But when I add a coupon to the same order it all goes wrong. The problem is that in magento if you use a coupon he deducts a % on every products, after that he is giving the cheapest for free but with the wrong amount. Example The total is 89.80. Once I applied the coupon code -45 euro he reduces each item price by 50.06 % (becaue 45 is 50.06 % of 89.80 Now all the items in the cart has new prices. The module founds cheapest items and makes it free. See screenshot The correct amount would be 29.95 excluding shipping which then need to be added. Who can fix this? Amasty itself is unwilling to help.