[LisaS]

the only relevant numbers of course are the actuals. What you use for 3x10 sets is not your 10RM, but it is probably what comes to mind when someone mentions 10 reps. I think the charts and formulas are useful for lifts where you feel unsafe going for a true 1RM but OK trying for a 3RM (e.g. unspotted bench perhaps). But only in the context to use that number (derived 1RM) to calc starting values for other lifts/rep schemes anyway. Sometimes I take a weight that I know is a max somewhere between 2-10 reps for a given movement and then take it to max reps. Let us say I get 4. then I use the charts for 4RM to get approximate 1RM, 8RM, 10RM etc. to use in guessing starting weights for 3x10 or 5x5 or other rep/set schemes.

I hadn't heard the 8RM used for estimating fiber distribution (FT vs ST), but have heard actual 3RM compared to actual 1RM to do the same sort of thing.