When you bring the difference of aspect ratios into it, it becomes relative - psi (per square inch).
My 1990 Mk2 runs 185/60/14's, and my 2003 Mk4 runs 225/40/18's and both run about 28-30psi. There is no sign of over or under inflation, and always give me a positive feel, admittedly if I was going on a journey with luggage (or wife in the boot!) I would inflate the rear tyres accordingly
Like I said before I have changed ALOT of tyres in my 15 years, and I personally have never put this kind of pressure in them.
Lewy