IN AN AIRBUS AIRCRAFT; SUSPECTED TO BE HEAVIER THAN DOCUMENTED; WAKE TURBULENCE IS ENCOUNTERED DURING CRUISE CAUSING UNEXPECTED 30 DEGREE ROLL.

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JUST AFTER ROTATION AT PHL WE NOTED THAT THE PLANE WAS A BIT SLOW TO LIFT OFF AND THAT V2 WAS VERY NEAR (ONE OR TWO KNOTS) VLS. LATER IN CLIMB OUT; WE ENCOUNTERED THE WAKE OF A PLANE WHICH WAS; ACCORDING TO ATC; 9.5 MILES AHEAD OF US. IT ROLLED THE AIRCRAFT ABOUT 30 DEGREES TO THE LEFT. THIS SEEMED EXCESSIVE FOR A WAKE ENCOUNTER AND ALONG WITH THE PECULIAR V2 VLS RELATIONSHIP GOT ME THINKING THE WE WERE SIGNIFICANTLY HEAVIER THAN STATED ON THE WEIGHT AND BALANCE. WHEN I LATER NOTICED THAT THE PROG PAGE WAS SUGGESTING OPTIMAL ALTITUDES 3000 FT TO 4000 FT BELOW PLANNED; I DECIDED TO LOOK AT GWFL IN THE PARAMETER ALPHA PAGE ON THE MCDU. TO MY SURPRISE; FLT AUGMENTATION COMPUTER 1 INDICATED 136900 LBS AND FLT AUGMENTATION COMPUTER 2 INDICATED 135560 LBS. THE GROSS WEIGHT OF THE PLANE ON THE LOWER ECAM WAS 127800 LBS. WE RECALLED USING THE NEW TAXI CHECKLIST WHICH CONFIRMS THE WEIGHT ON THE WEIGHT AND BALANCE WITH THE LOWER ECAM. THE FO KEPT THE POWER ON THROUGH THE FLARE WHICH AVOIDED A HIGH DECK ANGLE AT TOUCHDOWN. I DO; FROM TIME TO TIME; HAVE A LOOK AT THE GWFL VARIABLE IN THE MCDU. IT TENDS TO FLUCTUATE 2000 LBS TO 3000 LBS; 9000 LBS IS VERY UNCOMMON. IT IS INTERESTING TO NOTE THAT HAD THE 'CORRECT' WEIGHT ACCORDING TO THE GWFL BEEN REFLECTED ON THE WT AND BAL; WE WOULD HAVE STILL BEEN LEGAL FOR TAKEOFF AND LANDING PERFORMANCE. CARGO WEIGHTS ON THE WT AND BAL WERE 60 LBS FRONT AND 2010 LBS IN THE AFT. PASSENGER COUNT WAS 110. IT SEEMS A MISTAKE WAS MADE COUNTING BAGS OR WEIGHING THE CARGO. THE SOLUTION PROBABLY LIES SOMEWHERE BEYOND THE INFLUENCE OF PILOTS.