My recollection is that once fuel went below 20,000 lbs it was critical to limit bank to less than 20 deg, ie - 20,000lbs is nearly empty. Don't know if CS BUF is so accurately modeled that it duplicates real BUF limits, but BUF fuel mgmt was a bear and required a lot of co-pilot attention. Just the recollection of an old-time BUF vet.