The coupon was not designed to stack with other coupons. It was one or the other. When you took the Vet discount it override the Memorial Day coupon. I am sorry, it seemed self explanatory to me. The 15% off was there until you clicked on the Vet discount and it took that instead.
Anyone who did this, call me tomorrow, so that I can get your info and credit you back the 5% that you missed out on. Next time I will add a note to the advertising that the sale is not valid with any other offers.
Again, sorry for the confusion.