hoboy.net is my own registered domain, so it can stay there indefinitely. Actually, there's also a copy at http://www.hoboy.net/formulas.xls
to cut down on 404's if you would rather use that address. Or, if somebody (maybe TW?) wants to put it somewhere more official that would be fine with me.
re accuracy, there had been a mistake in it when I first put it up last month, but it got fixed, and there have been about 300 downloads since then with no further complaints.