Could be a lot of things. I do 55% infill 3 walls, 2 bottom and 3 top layers. 30mm/s. Is that about what you had yours at, If so it could just be from the mpcnc acceleration settings.
Or…I did have these sliced with simplify, some parts it really saves some time on. A little smarter slice really adds up for a guy running 6-8 printers 24/7.