What about "U.K. watts"? I once had a Goodmans of England 18" hi-fi woofer I used for bass, the sticker on the back of it rated it at "100W RMS, 200W USA"Mesa=U.S.A. Watts (ie: big, meaty, real watts)
Alot of others, including almost all Asian built amps= Those 'other' watts.
Behringer= Little bitty pale green faded watts.