It probably doesn’t matter all that much, but it makes it hard to discuss. We never seem to have to speculate as to what Buhlmann GF or VPM-B ”really mean”.
(Edited)
Well for "recreational" as in no-stop diving with occasional overstaying of the NDL it wouldn't much matter anyway.
It's really about how you compute the extra "conservatism" on top of your basic dissolved gas model: a straight line, some convoluted formula, you can even change your off-gassing from exponential to linear under some conditions... what it "really means" is getting the diver out of the water not bent while satisfying some other design criteria. Like minimize their deco time. Or their risk of getting bent. Or something.