Well, a compression test should be done only after the valves are adjusted. Valves on my Civic (which i got from my brother who got it from our father) were not adjusted since we got the car, and first compression test showed VERY LOW measurements (8.2bars on one cylinder). After valves were adjusted they all jumped to 11bars.

Point of story: compression test can tell you how worn your piston rings are only if you adjust your valves before the test.