This is a great plugin. I was able to create a coupon and have it generate a new window to print the coupon in the preview screen. When I added the coupon into the post it created the coupon along with the link for to print but it won't do anything else.
If you enter the url of the exact file name it comes up and prints as normal.
The generated one in the post states "Click to Print in a New Window" where the url coupon states "Click to Print" which works flawlessly if that helps.