It dont really matter how you figure it for your own use... you can take 130V x 35A / #toes on your left foot + the height of the empire state building X eleventy... as long as you do it that way every time (and dont loose any toes) you can always compare the amps you've tested. You just cant reference anbody elses test because I wouldnt think they would do it that way. For simplicity sake I just multiply voltage and amperage from the exact same clamp and exact same dmm everytime... as well as note voltage drop and dcr that the amp sees. I've got tons of spl/output #'s from 20.1's and a few from 2500d's, but I've opted out of publishing these #'s so people (like sergio) dont think I'm giving bias'd info.
spkrman - the 3400-3500 I've seen out of the 2500d's was on unlimited voltage drop to less than about 17.2V and .7dcr to the amp. Most I've seen off a street app. (1 Optima Blue Top) Voltage drop to about 10.2V output was less than 1575W at .5dcr to the amp.