My apologies...misread and misthought. I will say this...the bias voltage is the voltage that determines current draw. Current draw is the thing that interests me the most. The same bias voltage with a different tube in a certain circuit can yield different current draw. This is why Mesa grades and sells tubes...and recommends that the player use that tube in their amp. I like to know what tubes are doing in the amp, and I like to be able to change tubes and adjust bias settings. YEs, I do vintage Fenders. There is a range of 'correct' bias settings, and across that range an amp can yield differents sonics.
Current draw is what I want to know...with proper concern and observation of plate voltages, of course.