well, Bardsley, what you say is true, someone who was learnt that the A vibrates at 440 hz will think that the entire piece is sharp if the reference is 445 hz. That's a drawback of perfect pitch, as if you saw colors so good that as soon as it's slightly off, you see a different one. Think about seeing mona lisa in blue instead of beige...(the contemporary artist who made all those colorful faces including the monroe one, must have had perfect pitch) :D