PatrickD Hi PatrickD. These values are given as general guidelines. On a new instrument, I can afford to go significantly higher—I don’t have a problem going up by even a full tone, for example. A new instrument can "withstand" much more. Even the first chip tuning is done at A4 = 460 Hz.
With an old one, there is obviously a risk—you have to be careful there, and generally, I never go more than 10 cents above the target frequency.
