that isn't the case because the head is bOwl shaped. you can take ten thousands off the first cut and C c it mark that number down take another ten off the head see see it again and it won't be the same because the bowl (dish) in the head allowed for more material to be taken. The second cut will not be the same as the first nor will the third. Example: first cut of ten gave you a cc of 27.5cc. Take another cut of ten and you have26cc.