I haven't seen this discussed before:
Shouldn't bombers have a maximum payload that they can carry that includes fuel and bombs?
It doesn't make sense that a B17 can carry 6K in bombs whether it is at 100% fuel or 25% fuel. It seems that you should be able to trade fuel for extra bomb load. For example, I've read that with wing racks, the B17G had a bomb payload of over 12K, but with a greatly reduced range.