I'd argue with that, from a fluff perspective
IMHO, cybertech of the same grade could be upgraded easily (depending on type, of course). The Reaction Enhancers upgrade could mean installing additional macguffins e.g.
As for Bioware, I'm almost completely opposed. You don't just add a lump of meat to an organ and it works better.
Off the top of my head, maybe bone density treatment.
Oh, and I calculate the damage of an operation off of the final essence cost (before dividing it) of the 'ware, as well.
Caveat, though: That's just my personal way of handling it, to my knowledge not supported entirely by RAW, just extrapolated. Not even a houserule, just flavour, really.