I've had an FP-4 for over a year now, and when I first bought it, I noticed that notes on the upper 2 octaves (starting with F) were distinctly out of tune from the corresponding notes on lower octaves...Both Roland & The Guitar Center insisted this is how a 'real' piano works... I do not understand the logic here - if I'm playing a solo and use any notes in those upper octaves, it sounds like I am playing in the wrong key.... how can this be 'correct'? I tried other FP-4s at music stores, and they all did this...yet other digital pianos did not... can someone explain?