P&Y trophy qualification question??

Ive heard some things about how your let-off weight can disqualify a record class buck from being put in the books. Anyone know anything about this? Ive been shooting a bow with hardly any let-off for about 6 years now. I shot one the other day with i'm guessing a 65% let off and it seemed to help my shooting a lot!! could have just been lucky, but it would definitely be worth lowering my let-off if its going to help my shooting. I just don't want to miss out on putting a buck in the books cause of my let-off percentage. Id have to get really, and I mean really lucky to bag a book quality buck but hey i can always dream right?