I wasn't faulting your process, only pointing out what can occur.
All machine tools are made to certain specifications. As long as they fall within the parameters set for each tool, then they're considered "in spec".
With that said, what I was pointing out was that if a sizing die is at maximum specification, it won't size a case as much as one that is at minimum specification. Add into that the specifications for expanders. If one is at the maximum, it will expand the case mouth more than one made at the minimum specification. The two of them working together cause what's known as "tolerance stacking". This can be quite a spread if both are at maximum specifications, or even minimum specifications.
In .38/.357 calibers, I have about half a dozen sizing dies. Some will work well on all brass, and some won't, due to the differing diameters of each one. This can, and does, occur within the same brand, since it's the nature of machining hard materials. A new cutter will produce a different size than a worn cutter, but both are within specifications.
I use a lot of Remington brass in many calibers, along with almost all other brands, (except A-Merc). Over the last 47 years of reloading I've learned some of the nuances of different brands of not only brass, but the tools used to reload them. You might say I'm cheap, since I'm determined to find a way to use any and all reloadable brass, but I prefer the term "innovative", since I like to tinker and figure out what makes things tick.
I've even found a use for all that darned .40 S&W brass that I've accumulated. I make jacketed bullets out of it for my .44 caliber handguns and carbines. Works like a champ and they look just like the Hornady XTP when loaded.
Hope this helps.
Fred