Ok, so some people say it's always perfect for them, but I've never experienced that with any guitar ever. So I assume "...to my ears" is implied, and that's important. 5 to 10 cents is more than enough to be a problem for just about anyone. 1 to 3 cents, after playing a full song, seems totally normal me. Some people won't notice that amount of detuning, others will go crazy. (I used to work with a singer/songwriter who could hear better than bats: it drove him, and everybody else nutty, chasing tuning issues that were of zero importance). That said, on stage I usually do a quick tuning check after every song assuming there is no segue to the next tune) and in the studio the tuner is used between takes. So even putting individual ears aside, what is acceptable is situation dependent.
With a floating tremolo as you have on the Majesty, JJBC, if all the strings go out of tune the same direction, that suggests the bridge is not returning absolutely perfectly to its initial "zero" position. If one or two strings are going out of tune in different directions of the others, then there are issues with individual strings either slipping or binding somewhere.
For lubrication, I also lubricate the top of the saddles but with peizo saddles don't use anything liquid that could seep into the piezo element/wiring. Lithium grease is my preferred lubricant. Next string change you could also take the bridge off and lubricate the posts/knife edges. I never do this, but if I did would choose graphite - liquids or grease can attract dust and dirt which might not help.
And of course, we are assuming high quality strings, relatively new and correctly installed. After 10 or 15 hours of playing time, I would not expect best tuning performance from any strings.
I'm gonna play my guitars for a while today and track how well they do.
