it doesn't matter... Iodine isn't your problem at the moment.
irregardless of what caused it, you need to fix the "it"
or you're headed for an even bigger disaster.
i'm not sure the high doses is a lifetime thing?? i started at 120mg and plan to cut back by 20mg a week until i'm around 15mg (2 drops of 7%) I think the reason why people start high is to avoid the bad detox affects and to become Iodine sufficient.
I don't know about the whole killing of the flora thing.. but everyone should be taking some kind of probiotic every day... even if it's just eating yogurt.