Still not sure what happened, but I really don't care. I just wanted to get some sort of undersrtanding of the play, because, to make the blanket statement, "...that you tack on for a personal foul on the defense..." is incorrect as a statement, if not irresponsible. Personal fouls follow basic spot enforcement rules, with the basic spot varying, dependent upon the play type, end of the related run, etc. If this foul occurred during a play before a legal forward pass was completed, then, if accepted, it would be enforced from the previous spot - not 'tacked on.' If it occurred during a scrimmage play prior to a fumble, it would be enforced according to the application of the 3 and 1 principle at the basic spot. For a Team B foul, that would be the previous spot, or the end of the related run, which might not be the dead-ball spot. Depending on the result of the play, it might be declined altogether. But, it definitely doesn't just automatically, "...tack on..."
Perhaps they got it right, after all.