Thanks for sharing, this is consistent with my results, and those in the literature as well.
While not intending to provoke an argument, I have doubts about the numbers in this statement: "I suspect I was doing somewhere between 5 and 9.5 mg a day with kelp and dulse for several months before that." The reason for this is because dulce and kelp contain very little iodine, in comparison with the doses that you have taken as of late, which would tend to support the notion that you were very deficient in Iodine for quite some time.