I was on the fence about that, but you’re definitely right that the extra features of a subsystem can change it’s categorization. My original idea with this was that most extra features could be considered separate subsystems, but design optimizations such as single stage vs multi stage and pass through are things I couldn’t account for without making the survey too long. I elaborated for drivetrains because most of thme are different enough that I could easily justify it, but I couldn’t figure out how to handle the other subsystem optimizations.
Personally, I think a pass through elevator and non-pass through is just a function of the width of the elevator and that that doesn’t majorly contribute to the resource intensity of the elevator, and while more resources are required for multi-stage vs. single stage, I wouldn’t think it’s enough to merit that much difference in terms of listing, but I could be wrong.
I think in the later stages of this project I will consider more of the “extra details” like the ones you’ve mentioned and find a way to accumulate them on top of the base structures (ie. For each stage of an elevator, there is n more resources taken up). I think in most examples such additions would be relatively linear, but I’m open to suggestions.