I have a Strat and Line 6 amp with the indicator light tuning on the floorboard. I had the intonation at the octaves set very accurately on a new set of D'Addario .009's. But after they were about 10days old, and averaging perhaps an hour of play time each day, I checked the intonation again, and the solid strings had gone way sharp at the octave, while the wound strings had gone sharp to a much lesser extent. Is this the normal or usual situation? Does this vary much with the brand/gauge?