The angle of the pic is a little funky, however it appears that you are rolling your shoulders to far forward. A back lat spread, from the rear, should be similar position wise as a front lat spread.
hmm, yes i do try to roll my shoulders in alot. I was thinking this would make the back look even wider, but now i see what you mean. It actually makes it narrower at one point.
I always try to lean back a little. When I first consciously tried doing this, from the front it made the area under my arms fill in and looked pretty damn cool (I noticed yates did this in his poses).