Hi All, just FYI, unless Sound Lab recently changed it, the name of the backplates is “Consummate”. These have the Toroid II AND Hot Rod features. If you’ve been searching the web for “Commensurate” you might get some more hits with Consummate.
I purchased my U1s with the Hot Rod update installed. Duke said the difference has to do with better passive parts including low noise Vishay resistors and more linear capacitors. Can’t give you a before and after perspective, but the improvements should be a more refined sound.
I did update to the Commensurate transformers which improved efficiency and bass response a bit. More output with same power.