Gameshape is a very weird thing,my C is this season struggeling with his shape too.
I let him play the perfect minutes,and all season his shape was 7,however this week he jumpes to 9.
Last season I didnt have any problem with his gameshape almost the entire season his shape was 9.
And last season I had trouble with the gameshape with my guards,seldom above 7,and this season always 8 or 9.
I think that gameshape is also a bit random .