So I've noticed when you fill a bottle to its max fill pressure of 4500psi, later after it cools down the pressure drops to like 4300ish psi. I know, laws of physics at work here not getting around that. My bottle is a 90cc pony from joe B. so I don't get many fills out in the field before needing a refill. Every bit of air counts to me, so I've been thinking how to use this to my advantage. What I do is put my bottle in the freezer after I fill to 4500 psi with the yong heng, let it sit in there for a hour or two. Then I pull out the bottle that now reads 4200-4300 psi, connect back up to my yong heng and top off back up to 4500psi while still ice cold. When the bottle warms back up to room temp. it will read 4800psi and give a extra fill for the wildcat.