The question is not how high, but why? In my paid concert venue I charged an extra $100 (should not be $125) for changing the pitch from 440 to 442 and back. I did make that change on one of the university Ds and it took me four tunings to get that damned thing stable again. Their nickel but it was my time and my responsibility when the piano went out of tune. I just absolutely refused 443. I was asked for 444 once and refused more vociferously. The more freedom given to change pitch the more it is taken and the higher it goes. We have a "standard" so let's stick to it. Ds are particularly sensitive to pitch changes, they behave like a collection of springs and not nicely either. If you explain to your chairman that you will have to spend the time to restabilize the piano that you could have done five more tunings for the department then the chair might have a better perspective on what such shenanigans cost. Two tunings before and two and maybe three after. And who the hell can tell the difference? My attitude is; "up their attitude" and not on my piano. Let them rent a piano from somewhere else. It is AMAZING how quickly they change when it is going to hit them in their Handtocha. Newton (mad as hell and I'm not going to take any more!)
This PTG archive page provided courtesy of Moy Piano Service, LLC