My contractor put in a gas line for a cooktop and used tracpipe so there wouldn't be any unions,etc in finished ceiling. He tested the line with 5lbs of pressure for 24 hrs. It dropped about 3/4 lb. He was ok with that saying the air cools, etc and the line doesn't have to support 5 anyway, that's just so they can spray the blue magic solution on the joints, etc. He said his test gauge is old and might have a very small leak too. He said to make me feel better he'd drop it to 2lb and do 24 hr. It dropped about 1/2+lb still in last 24 hrs. His explanation is that there is no leak, the gas company would test 1lb for 20 minutes and call it good. He's an engineer, and has 25 yrs in the business as a certified hvac, restaurant eq guy. Is there a legitimate reason for it to lose 25% of the pressure? Should I let him turn it on?