Im not sure why its doing that. Whenever I use the tester I end up putting as much air in as I can with it at tdc of the cyl Im testing. With my 454 I didn't have to hold the crank because when the piston was perfectly tdc on compression stroke the piston would stay in place. I know its right when I dont hear any huge billowing amount of air pouring out of an open exhaust valve down the tail pipe. Your looking for a very small oil leak vs a stuck valve or something like that which is what the tester was designed for. The oil is getting in the cylinder so the air pressure that you put in can also get out. You have to look and listen for the leak then. If you are trying to rule out the rings, you have already done that ops check. Although your numbers from earlier with your compression test were a little varied, then didn't seem grossly over or under and the compression test with dry then wet cylinders is a really good test. Keep at it man, um or woman, Ill keep helping anyway I can.
