Need Help Translating The Shootout Variables Of Dyno Dynamic's Dynos

[Moodles2]

I'm just trying to understand the variables at the bottom of my dyno sheet done on a Dyno Dynamic's dyno in shootout mode (I've just done educated guesses):

BP is barometric pressure (what does 100 mean)

RH is relative humidity (in percent?)

AT is ambient temperature (most likely celcius)

IT is inlet temperature (at the airbox?)

RR is rpm:road speed ratio ("015" not sure what this means)

TN i've been unable to guess (3.454 = ?, I thought maybe final diff ratio, but R32 GTR's is 4.111)

CK is ? (343)