No one is splitting hairs.
Faster burning powders spike (pressure) sooner as velocity increases, whereas slower burning powders spike later.
This is why there is a general practice of using faster burning powders for lower velocity loads, and slower burning powders for higher velocity loads.
Gas cutting happens when there isn't enough pressure to obturate the boolit. So if you have a undersized boolit, it's more likely to have gas cutting on a low pressure load, than with a High pressure load.