I'm relatively new to using a HUD (I've been using PT4 for a few weeks) and I've only just started using the Aggression Factor stat. I use pre-flop AF and total AF in my HUD. I understand that it is calculated by (total bets + raises)/calls. But there is a player at one of my tables who has a pre-flop AF of 0 (AKA 0 bets/raises and 1 or more calls) and a total AF of infinity (AKA 1 or more bets/raises and 0 calls). How is this possible? Don't these two stats contradict eachother?