Probably a controversial question
I’m not sure the best way to word this, but I think this example will do a pretty good job of explaining what I am trying to ask:
Person A measures 5.5 inches erect after newbie gains, and Person B measures 6 inches erect after newbie gains. If person A then gains .5 inches and is now 6 inches would Person A have as easy a time gaining another 1 inch as person B who was already at 6 inches, or a harder time?