52662812 the guy's salary is not below 11K
Out of the 8 guys that played for your opponent, the two starting guards have salaries $11328 and 11965, so I admit that should be "12k or lower" and not 11k.
As for the GS issue in the 2828 game, it really isn't a matter of what we believe, or what we want to believe. The game rating (especially for players who are no longer improving or losing skills) is very closely correlated to the gameshape. You're saying that he now has ratings of 11 with average GS and that he posted an 8.5 with strong GS, I find it very unprobable.
If your player can play PF and be effective it's a great thing. It means he has a good, diverse skillset, and is able to cause mismatches. But your statement was something like "my 7.7k
guard constantly outperforms 15-35k
guards", so it's an apples and oranges thing. If you want to compare the results of two experiments, they have to be performed under the same circumstances. In this case, to compare a guard's performance to a different guard's performance, they both have to play the same position. So either we look at the games where your guy plays guard, or at games where someone plays a more expensive guard at PF.