B727 CREW DEPARTED WITH INCORRECT WT AND BAL PAPERWORK.

Narrative

THE PERSON PREPARING OUR WT AND BAL PAPERWORK MISTAKENLY THOUGHT THE ACFT HAD AN INOP FUEL PUMP RATHER THAN AN INOP FUEL GAUGE. THIS CAUSED THE PAPERWORK TO REFLECT A REQUIREMENT FOR 12900 LBS OF UNUSABLE MEL FUEL. THIS MISTAKEN REQUIREMENT TOOK THE MEL FUEL FROM OUR AVAILABLE FUEL ON BOARD; SHOWING THAT WE BARELY HAD ENOUGH FOR THE REQUIRED ENRTE FUEL. THIS SAME MISTAKE ALSO SHOWED OUR ZERO FUEL WT TO BE 12900 LBS HEAVIER THAN IT ACTUALLY WAS (WE ASSUMED THIS INCREASE TO BE DUE TO ADDITIONAL FREIGHT). THE ACFT HAD BEEN FUELED WITH THE CORRECT AMOUNT OF FUEL REQUIRED FOR THE FLT; SO WE ELECTED TO CONTINUE TO OUR DEST AND NOTIFIED OUR DISPATCH OF THE ERROR ON ARR. THIS OVERSIGHT ON MY PART WAS DUE TO AN EFFORT TO GET THE FLT OUT ON TIME. THE INCORRECT PAPERWORK SHOULD HAVE BEEN DISCOVERED WELL BEFORE DEPARTING; BUT PRESSURE TO KEEP THINGS MOVING PUT US IN A 'GO' MODE TO MOVE THE BOXES. DISCUSSION AMONG THE CREW BROUGHT TO LIGHT THE FAILURE OF USING NORMAL ROUTINE AND CONSISTENT HABIT PATTERNS THAT WOULD HAVE PREVENTED US LEAVING WITH AN INACCURATE WT AND BAL SHEET.