Running RGB Full Range on the PS3 means you are running it with PC levels and not video levels, and for movies it will have to expand the range on it's own. While in theory you can see the same as you would from video levels, you will certainly lose light output, as you have to run the contrast level much lower to avoid crushing the 235-255 range of the spectrum, since that area now contains picture content.
Additionally, while content shouldn't have any information above 235, some material does and this will not be visible under any circumstances now, since your PS3 will stop displaying that material at 235 with a hard limit. If these settings are shared with other devices, then those will have shadows that are gray instead of black (since black is now 0 on your display instead of 16), and the bright whites won't be as bright as they could be, since peak white is now 255 instead of 235 as it would be on content.
My question is why would a professional use a PS3 and not a pattern generator for a source? They could use the PS3 to spot check the results, but it seems like a bad idea to use it as a source when having the wrong setting in them can mess up the output so much.