WELL, I went back to the stove top to boil some large and small eggs but only used enough to cover the bottom. Used cold water but added some baking soda AND vinegar, I wanted to make sure the shells would come off. Boiled for 5 minutes, off burner, covered for 15 minutes. Drained, shook pan with lid on, covered with cold water. Rolled gently on the counter to fracture shell all over and then they peeled very well with only 1 having a small flaw.
I will test with the IP again, but I have been done in by so many tests using everyone's timing. I had made a list of all the different times used and comments on results. I even looked at electric cookers to do 2 dozen eggs--I was getting desperate to have perfect eggs for the church funeral meals.