stability of pitch raises

[Tvak@AOL.COM]

I do all my pitch raises using RCT, so I end up very close to pitch after the 
first pass.  If the piano is 50 cents flat or more, I have always warned the 
client that a pitch-raised tuning is a less stable tuning, and that their 
piano may need another tuning in 3 or 4 months.   Rarely do they actually 
call me in 3 months.  Most often I come back in a year...OR TWO, and I am 
usually surprised at how well the piano has stayed in tune.  Not that the 
piano doesn't need a tuning, but it's tolerable enough that I can understand 
why I haven't been called back sooner.  I suppose it's possible that the 
piano did all its drifting in the first 3 months, and just stayed there, but 
I'm starting to wonder about the conventional wisdom that a pitch-raised 
tuning is less stable.  

Could it be that the use of the RCT negates the instability issue by virtue 
of getting the piano so close to pitch after the first pass?

Any thoughts?

Tom Sivak