Cannon Custom Printing review for Magical Sale Price Manager

I thought this was the cat's meow until I discovered that it can't/won't add all of my items to the sale. I have over 500 items that I wanted to do a Flash Sale on, and after numerous attempts, I can't get all of the items added to the sale. It would also be great if there was an "Select All" button or something so you don't have to individually add each item. After searching for said sale items, it would make sense to me to have the "Select All" function considering you've already narrowed things down.