AbleCommerce Shopping Cart Software

I would like to offer a discount of $5.00 when someone orders Product X. However, if they order 2 of Product X, I only want one discount to be applied of $5.00, not $10.00. I have tried the Coupon Codes as well as the Volume Discounts but can't seem to make it work.

Or if there is a way to save $5.00 off of shipping if one or more of Product X is ordered.

Under Administration > Configure > Store go to Volume Discounts section and then change mode to Group By Category. Now it will add volume discount once for one sort of products.