The original question was because the operator, who I suspect is the NZ Air Force sits on the tarmac with the APU running for hours on end. My experince is that the 757 APU will burn something slightly less than 200 pph with all the packs and other elecrical draws up and running while waiting for Mr. Big Shot to arrive at the airplane. If no corrective action is taken for several hours a imbalance of five or six hundred pounds will occur and even though within limits, I suspsect the crew will want to balance it out as a matter of good operatng practices.