Naturally, after I got done geeking out about the technical details, one of the first things I considered was the specifications presented for the BA-2100 (now dubbed "Olympus," which I think is appropriate for a module that has greater volume than Skylab, Mir, and the International Space Station added together) and whether they fit my calculator's predictions. The results were troubling: the calculator underestimates the module's volume by almost 300 cubic meters, and overestimates the mass by almost 20 metric tons even on my lowest predicted equivalent density.
This error was pretty significant, and so I decided to double-check the calculator against the provided figures for the BA-330. This module was one of the ones I used to calibrate the calculator when I originally created it, so it was perhaps even more troubling that the predictions were also off for the BA-330: The volume was low by almost 100 cubic meters, an underestimate by almost a third.
Therefore, until I've had a chance to look over the new data and diagrams, re-examine my assumed model parameters, and put everything together, I'm retracting the model. I'm going to have to figure out what to do about the calculator (what's wrong, whether I can fix it, and what to do in the meantime), but I wanted to put this out there.
tl;dr: I've found some mistakes in my model based on new data. It's down until I can fix them to my satisfaction.