In theory yes,in practice no.Have you ever compression tested a subaru engine hot and cold? VERY little difference.
The question was whether different cams could affect compression gauge readings. The answer is yes.
To see how much, a cold test should be compared to a cold one and hot to hot w/the cams as the only variable.
"no pressure condition" Huh? Whazat?
A weak battery will affect results hot or cold, in or out of
the car.As long as you have consistent cranking rpm you`re OK.FSM suggests 250-350 rpm w/corresponding pressure variations.