Were you taking the 200mg as a split dose or all at bedtime? If it was all in the evening then the drug simply was at lower levels during the day whereas now it is more constant.

I have been on different doses always either split doses or 3 times a day. I prefer a split dose because then I can take the daytime dose after I have gotten up, showered, and fully woken up in the late morning. I eventually got used to the late morning dose making me tired and the evening dose doesn't really put me to sleep. I can't take the ER form since insurance doesn't cover it, so I don't have the experience there but from the sounds of it I might prefer the lower morning levels so I can get moving.