Most facilities give out “one size fits all” instructions and it’s on you to communicate with your Doctor’s office to tailor the instructions so as to be suitable for a J Pouch. To answer your question- yes it sounds excessive, I was directed to do a half of one bottle and a Fleet enema.
On the other hand having sat sober in a recovery room you wouldn’t believe the number of patients that cheat on these instructions resulting in bad tests and being ordered to retest because they were not clear. I have personally overheard patients being spoken to in the very busy Yale scope recovery room about this....
If you do the two bottles, I suggest stocking up on some reading materials and books in your toilet. Put a toilet stand near the commode with books on it. I would suggest War and Peace by Tolstoy- could be a good opportunity to catch up on reading some of the classics!