It does seem that the Guards will generally shoot more that the bigs on inside iso and the bigs shoot more than the guards on outside iso.
Not saying you are wrong, because ive already had this discussion with lots of other folk on here.
But when ive played OI, my SG was taking most of the shots. not always, and usually in conjunction with another player. sometimes SF, sometimes PF.
In a recent game, SG and PF took majority of shots. (like, 25 and 21 shots).
The SG took a full on variety of shots. Jumpers, 3's, driving etc.
The PF took majority mid range, driving/dunks/inside .... but NO 3's.
they both had about 50% of their shots being assisted shots. the other shots obviously taken of their own accord.
The conclusion i came to, was that with OI, the game engine isolates the best 'outside' player..just like the game manual says.... however what he does with the ball after that is going to depend on his skills and the opposition. The 'best outside player' is also going to depend on ur opposition.
eg: Your SG has the best JS and JR, but he is up against a team with awesome outside defence. However your PF ahs quite good JS and DR, and his opponent, is crapola. Therefore i would imagine the PF takes majority of shots.