The pic i saw of you, you had good definition but no real abdominal definition so that would probabl put you at 2-3% higher then your estimation. I dont think Martins formula is meant to be entirely accurate, just a good reference point.
Why dont you get on some Supplementation? At your age and level, i see no reason not to if you are interested in it.
As for my limit, i have wasted a lot of years and am not even close. Luckily i still have a good decade before strength peaks.