1st of all don't just look at the rating, because its only an overall estimation mainly from ur PF,C reb skill
1. pace of the game affect the total number of shot = total number of rebound available reb for grab, but not the rating
2. amount of enthusiasm and playing attitude do affect all rating
3. the % of minutes distributed to your good rebounder and bad rebounder at the PF, C have effect too
4. if u can match a good(reb) outside player in the lane, u can get good result even with lower overall reb rating