They should sit around 330 with .20s on GG/ Propane (if that), a bit more when the gas is very warm, less when the gas is cold.
The pop can method is highly unreliable. It'll give you a very rough ballpark, but it can't be trusted as results are inherently unrepeatable. I'd actually be very surprised if your gun is shooting 360-370 unless your house is over 30C.
Under those conditions they tend to run into malfunctions where the valve knocker won't be able to hit the valve hard enough to open it.