General rule of thumb, spamming "refineries" is the worst tactic in the game. Only if you have a sweet, sweet planet, would you put refineries. Astax had such an awesome spot last night, but that only means you put 4 at that planet and no more.
Trade on the other hand...yeah, that stacks until the cows come home.
BTW, Astax, for the record, that was the most awesome planet setup I ever saw for refineries: 1 dessert connected to 4 gas giants with 3 extractors each.