An option needs added to the "Exemptions" drop down, say "Applied Discounts Only" or "Coupon Exempt" that will allow only an assigned discount on the product so a coupon cannot be used in conjunction with the discount. The current "Product Discount Exempt" removes all discounts, not just coupons. This would be very helpful when running promotions.

Marshall
CENLYT Productions - ms designs
Affordable Web Design
Custom Ecommerce Designs
Responsive Websites
Cenlyt.com