The tiles are placed on a curve, so what they usually do is cut the large tiles into shorter segments so it looks like a curve. The 12x12s are cut into 4 - 3x12 inch sizes. When you run your hand over the tiles, you can feel all the sharp edges.
For our tub, the tile guy got chicken wire and mud and smoothed out the bathtub curve and then put the 2x2 tile sheet on top. That is the proper way to put the tiles down. I hope that makes sense.
I'll have to post pics when I get a chance.
Retail is for suckers.