It sounds what you are talking about is total Iodine saturation and I've never heard of this ever being reached by anyone. In my mind "iodine sufficiency" means having more than an adequate amount of Iodine in all bodily tissues so that the body functions optimally and w/o risk of illness caused by a lack of Iodine (or excess bromine/fluorine). Even the iodine doctors look at 90% excretion within 24 hours of consuming a 50 mg iodine tablet as a sign of iodine sufficiency. I question the validity of this, ... it sounds a bit arbitrary.
I'm not sure what the right answer is. We simply don't know how much iodine a body can hold and how much it presently holds. Same goes for bromine and fluorine; I'm not sure we know how much of these toxic substances the body can safely tolerate.
Folks on the Iodine Support forum would probably suggest taking 100 mg of iodine/iodide indefinitely to ensure sufficiency. For me this is at best a financial waste. Harmful? I really don't know. Consuming so much iodine certainly isn't natural, not even close. But I have yet to read of any harmful effects other than transient side effects.