If the cathode resistor is the correct value, and the voltage across it is
correct, then the power drawn by the tube is correct. The tubes are running
Class A and so over half of the power consumed is dissipated by the tubes
(divide by 2 of course). You can increase the cathode resistance or
increase the screen resistor, to reduce power. This could cause a mismatch
in the output transformer ratio, but being Class A, it should still sound
fine.

Generally, what I would expect you would be seeing (actually, feeling) is a
combination of small factors. The filament voltage is probably above 6.5
and the plate and screen voltage may be a little above specified. This is
because we have a higher line voltage. Often, you have to think about
incremental improvement, rather than night and day. If you drop the
filament voltage about .5 volts, you will decrease heat from the tubes by 1
watt.

Also, adding a small muffin fan can do wonders to remove heat from those old
metl boxes.

73, Colin K7FM