[Gmecm] Natural gas law

[Rob Handley]

I've been trying to match the $58 BPW calculation with a hand made BPW 
calculation spreadsheet - which is based on the natural gas law.

What's confusing me ATM is that, in $58, the inverse air temperature 
correction factor (array F31M) does not change when the MAT value is >23.5 
C.

Since gas mass is inversely proportional to gas temperature (if pressure and 
volume are constant), the MAT contribution should have an effect at all 
temperatures, and this effect IS significant above 23.5 C.

What am I missing?

Rob