It is very frustrating and it wouldn't be a big deal if it was an element but frames have to be exact.. I have tried printing (not borderless) and it is fine that way BUT, there is a 1/2 inch or so of white around the entire paper. I don't like the look of it all. I know I can trim it and then mount it on card stock but the scissors/paper cutter and me don't have a good relationship.
I contact Red River Paper to see what they would say since I bought the 12 x 12 from them and they are usually pretty good. AND he said that yes, the Epson does have that Expansion problem and I should try the following:
You may have to do a slight cheat. Try to determine how
much of the image is getting cut off. Try and be as accurate as possible.
Then, reduce the 12x12 layout by that amount. For example, if you are
loosing 1/4 inch then make the file 11.75" x 11.75". It may sound weight
but I think it will work without any loss of print quality.
But I am not sure where in photoshop I would do this? Canvas size, image size?