Look Like a Bodybuilder, Perform Like an Athlete: Why MTW Minus 20/30lbs vs MTW Minus a %

When determining weights, I’m curious why use the MTW - 20/30lb as opposed to MTW - % of MTW.

If someone has a MTW of 400 and another has a MTW of 200, would the impact of subtracting 20lbs be pretty different - i.e. the 400 - 20 isn’t too noticeable, but 200 - 20 is.

Thank you!

Maybe more advanced lifters can operate at higher percentages more comfortably.