I did most of my searching a few years ago about the MV transporter. We had a poster here who used ALA and B5 alot every day, and so I did find that link to biotin also being unable to be absorbed or transported in the GI tract, when the transporter is filled.

After some searching for you, I found that Iodide has been added.

All of the supplements seem to be microgram quantities in food.
In fact, ALA is almost non existent from food sources.

So the logic follows for me at least, that in order to get good biotin absorption and transport, the others should not be in high doses. Just 100mg of ALA which is a small dose compared to the studies for neuropathy which are hundreds of milligrams, would overwhelm this transporter.

So you could try just not using the R-lipoic acid at all for a month, and see if you note any changes? That might open up the transporter to move your biotin to the tissues better?