I really can't get into a protracted dialogue over this I'm afraid.

I've never had anyone complain that they have been hoodwinked or duped or misled into buying the wrong bottle. Quite the reverse; many have written to say how close the predictions are to their own experiences. I know that is only their perception and that it almost certainly differs from actuality, but for many folk their perception is 90% of reality.

Writing code to fit the Van Der Waal correction when only two points on the curve have any relevance, i.e., 232 and 300 bar (as bottles aren't rated as far as I know to any intermediate values) would be a waste of time and I don't rise to such challenges any more.

ATB