Does steps per rotation change from part to part?

I’ve been getting inconsistency with results on rotary projects. The culprit appears to be (or my ability to influence the end result is through) the steps per rotation. I originally thought this was a constant value that never needed to be modified once set and changing the diameter entry in the rotary was the way to influence it. I’ve been speaking with Omtech support and they advise that it might change depending on sizes. To me this just isn’t sitting well. I’ve read conversations that advise one single value is all that is needed.

Is there anyone out there that regularly has to calibrate their steps per rotation before each time you use it? Typing that out seems even more nuts now that I say it. The only way I can do this is to apply some tape to the cup or whatever and measure that the dimensions line up properly before each time!? Something seems fishy.

please just give a yes or no if you have a sec
thanks!