I've never understood that part of the Avia disk either. I try and calibrate it to my mains then eventually give in to the temptation to adjust it myself anyways.

Also, I don't have the adjustment table for my particular SPL Meter's inaccuracy for LFE. I have seen downloadable tables for the Radio Shack meter but that is a bit of a Holy Grail device here in Canada considering we haven't had a Radio Shack in many years since they pulled out and got replaced by "The Source".

With great power comes Awesome irresponsibility.