I have noticed that after filling and carbonating my 4th keg in my keezer, I am getting a little less pressure out of the faucet on all of my kegs. Is this normal? My thoughts about justifying this is that there is more air space for the tank to fill which takes longer to equalize as you're serving beer out of the faucet. I assume it doesn't necessarily affect the carbonation levels since it should equalize shortly after closing the tap. Am I correct?