The scoring is strange. You get a score for difficulty (so the more difficult your routine the more points you get) then you get scored of execution, starting at 10 (perfect) and going down.
So if your routine is a 6 in difficulty and you get a 2 point deduction, you'd get 6+8=14 points.
I think 15 is pretty high for pommel horse since the other guys got in the 13 range.