My interpretation is this.
Terry calls out CPR on transbrake 6r80
Terry at the beginning of the callout wanted to race CPR's transbrake 6r80 car, whether he owned it or it was one of his customers.
CPR gets lost in the callout and i believe interprets Terry's to callout to ANY car that CPR has built. (including cars that do not have a 6r80 and coyote motor)
Terry in turn agrees, but from what i see agreed to CPR's misplaced interpretation of his callout, therefore there was never a "meeting of the minds" in this callout. (because Terry is still under the assumption CPR is referring to a coyote transbraked 6r80, which seems to be incorrect)
Therefore CPR thinks Terry is backtracking on his callout, but he is not, there is just a misunderstanding regarding the terms of the race.
In my unbiased opinion (i have no relations with both of these guys), CPR has inadvertently misinterpretted the ORIGINAL callout by Terry, which called for any car CPR has built for a customer or his own car, that sports a tranbrake 6r80. Thus CPR feels Terry is backing out by bringing up the prior terms.
In regards to alleged excuses from both parties, i know nothing of.