Neil, I also Thank You.
It's people like You and Dean that make this so much fun.
I just won't remember what you said.
Once an acceptable temp is achieved and that measurement is used from then on, it matters not that it is properly calibrated.
In photography unconventional exposure readings are valid as long as the same conditions exist each time it is metered.
It could be the same in this situation.
D A M N E D the theory as long as it works.
Overexposed and under developed.......FREUD