that is about the best answer available. i will know.
as far as continued supplementation/maintenence, that is also going to be an individual thing. if you wish to be on a steady diet of mountain dew and burger king, 100mg might not be enough. if you diligently avoid as much of the bad halogens as is possible, then the 12.5-25mg windo should suffice. a hermit in the woods eating nothing but local plants may get along without any. halogen imbalance isnt the only thing to consider. heavy metals, air pollution and EMF are also serious considerations.