I am using the value that was calculated if it makes you feel any better :). It really doesn't make that big of a difference though, because if you set a req_fuel value to high, you set your VE values a bit lower, if you set your req_fuel value low, you set your VE a bit higher. I think the point is to get your VE values (not including boost) to be under or around 100% at peak. I know using the built in value for req_fuel, without including boosted areas, my VE maxes at around 70% (going from memory). If I changed my req_fuel down a bit, I could get that right up to the 100% mark and simply scale my VE table (it has built in functionality to do this). I don't really know why people don't use the default value, but once my wideband gets here and I can better tune this thing, I'll let you know if I find out any reasons to change said value :).