I had the same situation, my neurologist was pretty certain I had an inherited neuropathy, and no possible treatment, but she wanted to be sure. It really seemed to bother her because I was only 47, with 5 kids, and this progressive, incurable condition, and all they could do was prescribe pain meds. She sent me to Johns Hopkins, less than a two hour trip for me. The findings were not substantially different, but they did the skin punch biopsy and some of the Athena tests for CMT, as well as a two hour EMG / NCS. Diagnosis - severe small and large fiber polyneuropathy, probable CMT. I also have pinched nerves at wrists and elbows, but test for HNPP was negative.
So my two doctors didn't disagree, and they both supported my decision not to pursue further Athena testing since there is no treatment, but they more or less washed their hands of me and referred me to my family doctor for pain management. Actually the doctor at Johns Hopkins was happy to pursue it if I wanted to, but did say it was unlikely to be productive.
Dr. Smith's advice is sound. Additional tests for untreatable neuropathies seem pointless, but if there is some condition that is treatable for which you haven't been tested, by all means pursue it.