I have a Conkin 7 string guitar which has Sperzel locking tuners and a two-point trem, but I'm finding that when using the trem (gently, no Steve Vai acrobatics) the tuning is drifting pretty significantly almost immediately. I thought the point of locking tuners was to mitigate against this? I have had Floyd Rose types in the past that were rock solid, has that just distorted my expectations? The tuning is very stable if I leave the whammy bar alone...