[amioran]

The AI being able to get much more rebounds than the player is a well known issue on higher difficulties. In my testing offensive rebounding needs to be about 7/8 higher than the defensive rebounding of the CPU and about 4/5 for the contrary for it to be balanced (however it also depends on how good you are at boxing out etc. - I admit I'm not the best at it).

Another impactful slider on the matter is vertical (all physical attributes for the CPU are hardcoded higher for the CPU, some testing in the past has shown to be about 4/5 points of difference in HOF).