If you're still trying to understand what exactly BART and its unions are fighting over, you're not alone. Obviously, the fight is over compensation, but many of us are unclear as to what each party is really asking of the other. Even bargaining representatives on both sides are having a hard time agreeing on the factual differences between their own proposals. Last Wednesday, union and management teams sat down just to clarify some of their financial assumptions — assumptions that have led to multimillion-dollar disagreements over what each side is truly proposing.