CBTO the same with every bullet?

[NDSwede]

Thanks everyone for responding. I understand it better. Each person added something to understanding it more.
I recently measured 100 6mm Speer 100 spbt bullets and the lengths to ogive varied 12 thousandths from shortest to longest.
Also measured some Hornady 103 ELD-X. They only varied 1 thousandth from shortest to longest.