You have to remember these flights are operating into one of THE most difficult airports on the east coast to operate in and out of. Although now retired, I operated out of there for quite some time and it was not uncommon to hold on VFR days, to spend :60-90 just getting to the active for takeoff.
Based on my experience and knowing how everyone wants to find the magic formula of just enough fuel but not too much, I would say that each flight would likely require a different fuel load unless you are planning on landing at BGR or BOS because you can't get into PHL. <G>