Yes, same as psilocybin. When you microdose you are not supposed to get psychedelic effects. The supposed benefits come from prolonged presence of the molecule in the body. Similar how antidepressants work, the point is not to take one tablet once.
The effects of microdosing begin on consumption and end on discontinuation. They do not build up and fade slowly. Tolerance and breaks are frequently discussed.
So, it's not about the effect of a prolonged presence.
Not sure what other people are using, but I've worked up to about 64mcg/day.
100mcg is usually a full dose. Usually micrososing is 1/10th of a typical full dose so 10mcg. Your tolerance is already quite high if you're at 64mcg/day and not actively feeling any tripping.