John,
The doctors at Mayo Clinic in Rochester did a similar test on me last fall. They say my pouch is not emptying properly and the residual is what is making me miserable. My pouch acts like I still have chronic pouchitis, but other tests indicated I have "no active disease", evidently because of the Entyvio infusions I'm getting every 6 weeks.
They say what I have is Non-Relaxing Pelvic Floor Dysfunction, and I am scheduled for a 2 week therapy session at Mayo in August to retrain my pelvic floor muscles. Evidently my muscles are squeezing instead of relaxing when I try to "go". They say this condition is more common when there are complications in the take-down surgery, of which I had way more than my share.
Sounds like you may have already had a similar therapy. I am not overly confident the therapy will help me, but this seems to be my only hope for improvement. I'm having 12-14 BM's a day and almost constant pouch discomfort and sense of urgency for the last 3 years :-(. My pouch is 18 years old and I've had chronic antibiotic resistant pouchitis since day 1.
I hate my pouch, but hated the ostomy I had for 6 weeks before my takedown even more.
I hope you are getting some relief.