THE releveling is in first floor ? if yes maybe you need adjust low pressure adjustment
how do you know the seals are good? is it teloscopic jacks? or single stage?
also do this
power off with car level at floor
wait 10min and see how far the car drifts down (record this measurment)
Restore power level up car
repeate but this time hit the shut off valve in the motor room
wait 10 min
this will tell you if its leaking through the valve or the piston