With Hashi your TSH will spike up and down often at times. Your antibosies are attacking the gland and will turn everything upside down until they level off.
Did you have any antibody testing done?
Ideally - you stated you know where you feel your best at in your TSH.
That's good - most do not know where their ideal is.
I feel my best around a 0.04 which is very low - but it wears on me at times too.
my best tsh level is between 1.0 to 2.5 i am now taking 150mcg of synthroid. so far so good
What TSH level did you benefit on?