Hi Jeremy,
Yes, it's correct that you wouldn't change your ATD dose if FT4 and FT3 are optimal and TSH is low unless you're on your initial starting dose of meds. If you started meds around 6-8 weeks ago and had high thyroid hormone levels when you started out, you'd now lower the dose slightly.
If TSH is low and thyroid levels are normal and there's no TSI, this would be subclinical hyperthyroidism. If you started out like this, meds wouldn't usually be used. If you've been on meds and these are your levels now, you would Not increase your dose to get TSH to rise. Your thyroid status in Graves' is dependent on your FT4 level. If it's normal you're considered euthyroid (normal thyroid function) regardless of TSH. If you increased your ATD dose, your thyroid hormone levels would likely fall too low. best, elaine