If you feel fine, then why don't you compromise. Have your doctor run a Free T4 and a Free T3 to see what your hormone levels actually are. See if you can drop back to 112mcg and stay there, or if you need to drop to 100mcg.
The way you feel is more important than your TSH level.
Also, there are a couple of conditions that suppress your TSH, and you might want to find out if that is the case.
No, the Dr. is not running a Free T4. No, I was not originally hyperthyroid because my TSH score at that time was 167.3. After taking 125 mcg of Levothyroxine, my TSH stayed basically in the normal range for about 20 years. My age is 59. I feel perfectly normal with my TSH so low.
Have you had adrenal testing done?
Is the doctor running a Free T4 test when you have your TSH tested? Is it possible that when you developed Hypo symptoms that they were actually Hyper symptoms?
It is possible to go from hypo to hyper for several reasons. In this case I am wondering if your med dose is too high.
I don't know your age, but our bodies change over time. It could be that your thyroid hormone needs have changed, and the dose that worked so well for all those years is now a little more than you need.
How do you feel with your TSH this low?