NDT vs synthetic combo drugs?

So I wanted to ask a question about NDT vs synthetic T3 and/or T4: I've been having a lof of unpleasant hyper symptoms on NDT lately, and decided to go back on levo only which so far is working OK for me. No ups and downs as with NDT which is good, smooth energy levels, although I have not been on it long enough to know if there is going to be any long-term side effects (diagnosed with Hashi's 20 years ago).

My doctor said I might consider giving Novothyral a try. It's a synthetic combo (each pill containing 100 mcg of T4 and 20 mcg of T3). She said she has some patients who prefer it to NDT, but she did not specify why. This would equal taking 100 mcg of Synthroid and 20 mcg of Cytomel.

I know some alternative practioners in the US claim that NDT will worsen autoimmune conditions such as Hashi's since NDT contains allergens; however, I did well on NDT for years so doubt that is an issue with me.

However, from a financial point of view, switching to Novothyral would be really beneficial since 85% of the cost would be reimbursed by my health insurance (whereas NDT is not since it's considered organ therapy so experimental thus not reimbursable).

No matter how much I like my doctor who is open-minded and not like most doctors treating thyroid disorders, I feel I have to ask: how likely is it that a person having done well on NDT for years before developing hyper symptoms would do well on a synthetic T3 and T4 combo? Would there be any benefit switching to synthetic T3 and T4 rather than continuing to take NDT or switch to T4 alone...?

If anyone has taken Novothyral (Thyrolar in the US I believe) and NDT and can compare the two, I'd be most interested in hearing about your experiences!