OK, here’s the promised update to my registration saga:
The paperwork I got in the self-registration packet that was FedExed from California along with the Ohio title wasn’t enough. The final bill of sale included in it only showed the total purchase price, and the people at the Secretary of State were going to use that as the base price of the car. Fortunately, I brought a copy of my vehicle configuration (1st page of the purchase agreement), which broke out the base price as $35k and the options itemized separately. After walking them through that, they agreed that the base price was $35k.
I would recommend that before you leave the desk, check the second box on the third line of the Application for Michigan Vehicle Title — it’s the fee category/weight box. It should read “000035E” — the numbers mean a base price of $35k, and the “E” is for “electric”. (I guess if they don’t put in the “E”, that could save you the EV fee...)
I had already done the thing where I put another year on my previous car’s plates before I sold it — when I transferred the plates, they didn’t hit me up for the EV fee, so that was a bonus. (Not to mention the previous car had a lot lower registration fee, anyway!)