My question is what is the correct procedure to check hydraulic level in the tank on a Terramite TC5. The fill cap is threaded with the dipstick on the end and is the level read by placing the threaded cap on the tank or should it be screwed in tight and then unscrewed to read level? The difference in those two ways of doing it can result in a level difference of about 1/2 on the dipstick level.