Biasing signal tubes on a tube power amp/Quicksilver M120


Took possession of a new pair of Quicksilver M120 power amps with the KT150 tube upgrade a few weeks ago, am in the process of break in with about 70 hours so far. About 30 hours in I noticed that a 12AU7 tube had started to flare up when that amp was turned on so swapped that tube to the other amp and it followed the tube, I contacted Quicksilver and he told me that this is not a concern but to please switch that tube back to it's origional amp as the amp was biased for that specific tube, now my question is if I wanted to tube roll these 12AU7 or 12AT7 tubes am I out of luck and what happens when it is time to replace them as they wear out, are my tube rolling days over or are they just limited? What say you?
tooblue
@seikosha , @yogiboy , For clarity on my original post, I used the word bias when referring to the 12AU7 and 12AT7 tubes on my newly acquired Quicksilver M120 amps when the term balanced should have been used. 
@tooblue Did you figure out if you need to balance the 12AU7 on the QS-120 ?
I just purchased a pair of QS Mono 60 from QuickSilver ( not on the Website yet)
I was wondering if i could tube role the 12AU7 without balancing ?
A_shah
@A_shah, yes I was informed by the builder that the signal tubes do need to be ballanced. 
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