anyone with screen grid voltage higher than plate voltage in Deluxe reverb?

[7xa12]

I have screen grid voltage higher ( about 10V) than plate voltage in my fender deluxe reverb.(clone) with JJ 6v6 tubes
( all tubes , speaker and reverb tank connected)
470 Ohm screen grid resistors seemed to be ok. The amp is curently biased 16ma. with 440~450V on plates.
I have a litlle experience with amps.