Tab, when they start our meds, they usually start at the full therapeutic dose rather than tapering them up, so I would think you should just go back to the full therapeutic dose all at once.
As for fiber, I think we all react differently. When I'm flaring, I need as little fiber as possible. When I'm in remission, I tolerate moderate amounts of soluble fiber, but still can't eat things like oats, bran, and so on. If the change came two or three days after the fiber, you might try cutting it out to see if that resolves the problem. Usually the only way I find out what works is through trial and error.
Left-sided UC diagnosed 2001. Taking Colazal and Imuran, Remicade infusions and moving into remission. Finally off steroids after four years!
Now in remission for almost two years. Remicade has been my wonder drug.
"If you spend your time second-guessing your past decisions, you'll never have time to enjoy today."