Hi Snoel,
I fully agree with the max limit of 10 % at each step for Pred tapering. And that should also be valid below 5 mg. I was down to 4.5 mg/d when I had a relapse for another reason 6 years ago and I haven't recovered yet. I'm presently at 6 mg/d and one Plex every two months.
Maurice.
PS: Now I know the reason for your enormous Mestinon dosage...