Posted elsewhere, but can't seem to generate a response... one more try:

Would someone please help me understand this concept better? My initial thought is that you would want to measure the temperature after all cooling mechanisms (including meth or water) in order to compensate fuel for the denser air charge. The sensor is, after all, placed after the intercooler. This is obviously incorrect given the above discussion. Why wouldn't you measure the air temp after all cooling so as not to lean out with an unmeasured denser air charge?

My air temp fuel correction table below for reference. Thanks in advance!

 

From my understanding, the hotter the air, the LESS oxygen. It is less dense, thus you take out fuel to maintain the A/F ratio. But because the mixture is hotter, you take out timing.

That's what I've determined looking at various maps (trolling the standalone section )

 

I think the idea is that since the small IAT reduction (cooling effect) due to evaporating the water will be essentially negated by the oxygen displaced by the humidity increase, the net fuel correction is small enough to be ignored.

Perhaps, but I suspect running >25% meth is another story and should be corrected for.