near impossible tuning

[A440A at aol.com]

Greetings, 
   While I am wrestling with a bear, it occurs to me to ask if any others 
have also,and what perhaps helped. 
I am dealing with a 4 year old Kawai RX-6 that is giving me more stability 
problems than any piano I have dealt with in 30 years. It is in a large church, 
full amplification, monitors and everything, however, it is not being played 
excessively hard.  The humidity is far more consistant than many other venues I 
work around, and it has a complete humidity control system.  The pins are 
plenty tight,etc.   The problem is rendering!  
      It occurs in the capo sections.  It is one of those pianos that feels 
like there is no friction on the capo bars or string rests.  I have had unisons 
with 5 cents in them appear before I finish the tuning, and while I can 
usually finagle the obvious wild unisons back into place, by the next day, there is 
always a few with a cent or two showing up.  
      Anybody else run into this and find a magic, silver bullet?  
Thanks,

Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html