Moderators, I hope it's ok to share my personal experiences of tapering off postop with zero withdrawal; this was what I did following abdominal surgery and after 4 knee procedures:
before increasing the hours between doses - taking incrementally smaller doses at the same time interval.
If six hours is currently my comfortable interval, I cut the pill in half (and make sure I slightly increase plain acetaminophen to compensate, staying within safe limits). After three days, I cut the pill in quarters, adjust the plain acetaminophen. After three days, THEN I increase the time interval.