it's consistent w/ others, not only Porsche but most mfgs. Might be a "reduce the liability" issue so people can't come back and say they were caught speeding due to low reading speedo - erring on the high side of course
Anyhow, yes I'm pretty sure can have it calibrated to read correctly. Incidentally, you'll note it's not a 'linear' over-reading. At least on my '99 I never found it to be. For example, if I was really doing 40, it would say 44. If 70, it would say 74MPH...
YMMV - pun intended of course
