I didn't feel any difference whenever I surpassed 100mcg daily . It was a waste and a lot of guys have said that as well.
If I were you I wouldn't go up past, 60mcg , considering your thread with igf review , it sounds like your responding well at lower dosages,
But back to your point, yes once you hit your peak threshold let's call it, then anything more than that you would not feel like you did going from 10 , to 20 to 30mcg
Not sure I explained it well sorry