I would not go off Asacol without 2nd,3rd opinion. Ascol is safest medicine for UC and once you are off and if it is UC,Asacol may not work and you might have to go on less safer medicine.
I was in remission on Asacol and decided to go off. In few months hit the flare which required 9 months of prednisone and started 6mp. Still not 100 %. So please don't make that mistake.