I have a BCIR, but have never actually measured my output. My guess is that my pouch is quite large, perhaps similar to yours, and I have gone up to 12 hours between emptying it. The range of 500-900cc is normal for a k pouch. If the “pain” occurs only when you pouch is reaching its capacity, this is normal and provides a signal that it is time to empty. If it occurs at other times, it may not be pouch-related and could require medical attention.