C'mon, you are talking to nerds, here! an internet forum?!? rational?!?!
If it went up to .270 and could still drop down to ~.240, i'd be all good with it, because it could in theory resemble the various eras of real life without chanign LTM/LT.
Still looks like a turnover is needed if you want a static set of LTM/LT. I don't like physics shifting

. I'd rather the ratings change stats over time. I've got a neat little spreadsheet for it.
Either way, clicking auto-calc every ~3-5 years for 15-20 years isn't so bad either. Plus, you'll likely set some records that you won't see again without extreme luck.