One more thing, if there is a drastic colour change (i.e. between darks and lights) then there needs to be additional stuff for the prime tower (which is why in many multi-colour prints, the prime tower has "infill" rather than being hollow)

If it was using many small bits of poop, the printer is more like "poop clean - pause - poop clean - pause - poop clean - wait a bit more - now I print" since if the poop gets too big it could damage the nozzle/clog it.

If instead it was a prime tower, the printer is like "whirr prime towerrr >> actual print immediately after"