My basal body temperature is always low no matter if I am hypo hyper or in between! I think it is just indicative of a thyroid disease rather than one specific type.
When you have Hashi's, it is good to get your free T3 into the upper part of its range and suppress the TSH enough to alleviate your hypo symptoms. With Hashi's , it is my opinion and experience that a TSH suppressed below the reference range does not automatically mean you are hyper, unless you have hyper symptoms to go with it.
To relieve my hypo syptoms, I had a TSH less than .05 for over 20 years, with no hyper symptoms. Others have not had to go so low on TSH to relieve their symptoms. To me relief of symptoms is the key, not the reference range on a hormone produced by the pituitary which, from what I've read, responds mainly to T4 levels.
They say if your basal temp is over normal you would be considered Hyper and if under normal you would be HYPO, but I don't consider that fact, I am Hypo with Hashimoto's, however recently (In 12 weeks) my TSH dropped from just over 6.0 to 0.078, which would make me a little Hyper at this time, but my Basal Temp is still below normal, and I still have the sensitivity to cold. So I would not base to musc on Body temps, they vary too much. Good Luck FTB4
You really need to be restested for TSH levels, etc. to really know. I'm not sure on the basal temp ......... others may be able to offer some advice but WELCOME to our Community!