It definitely takes some fine tuning to get what works for your system. You know, all it takes is for your regulator and mine to be off a couple psi, or our temps to be off a couple degrees to have a noticeable difference. If you think about it (not counting shake method, don't like it), if a half full keg got overcarbed at a set pressure where the full one didn't, every keg of beer would get progressively overcarbed as we emptied it.