I finally beat the final mission of Carmageddon 2, but now a weird glitch happens. Whenever I try to grab new APO slots from the maps, they simply don't add up! (No, I haven't maxed out on slots.) What's worse, after I finish a race, half of my already unlocked APO slots and points just disappear! The manual says that the game sells some of them when you run out of money, but I'm not even close to having 0 credits. What is this?

Ah darn, never mind. I checked the Carmageddon Wiki. Different race groups have a set max amount of APO slots. If your slot amount is more than the max, and you collect an extra slot, the slot amount decreases. It's a glitch.