Cranking compression

Again,I think my compression gauge is 10psi off. It zeros out at 10,not 0. I just rechecked #1,#2,#7 and #8. I checked them 2-3 times each and my gauge read between 190 and 200 which means it actually between 180 and 190. I dont have the money to buy a new gauge so im gonna have to use these numbers till I can get another tester.