Bias and Plate Voltage question for early Dual Rectifier

[Dr.G]

Hi,
recently I have measured the Bias and Plate Voltage of my RevC Dual Rectifier and compared it to my RevG and the PV was quite low for the RevC. I used the same 6L6 Str420 code grey tubes in both amps.

For the RevG I measured:
Bold/SolidState: 453 volts and 23mA Bias
Bold/TubeRec: 429 volts and 15.5mA Bias
Bold/SolidState: 368 volts and 17.5mA Bias
Bold/TubeRec: 350 volts and 11mA Bias

For my RecC
Bold/SolidState: 433 volts and 21mA Bias
Bold/TubeRec: 414 volts and 15mA Bias
Bold/SolidState: 382 volts and 16mA Bias
Bold/TubeRec: 359 volts and 11mA Bias

I read somewhere the the PV in the Bold/Solid should be around 460-470 volts. I can live with the 453 of my RevG but the RevC seems to be pretty low with 433 volts. Both amps are European versions and are wired for 230v.
Has actually someone measured the PV of their very early Dual Rectos and could confirm this or not???

Thanks