All of this is on Tesla, not the DOL. Tesla's "specialist" in WA had supposedly read the law and decided that they had to charge it on the whole amount they charged you (base + options + destination) because that is the MSRP to them. I wrote them back and forth for a few days and sent them the relevant RCW and WAC, and showed them where the definition of MSRP was (specifically no options or transport) and suddenly they changed their tune and started charging the flat $385 at purchase. It was Tesla that was too lazy to read the law.
DOL only comes in to play when you renew your car, which won't happen until mid-year for the earliest Model 3's. When it does, the DOL now has $35K in the database for the 3 so it will be no issue. That only took one email to the DOL to fix. Tesla was also too lazy to contact the DOL and get the Model 3 in the database.
Anyone that was over-charged was over-charged by Tesla, not the DOL. Probably been happening on the S/X too. If you want a refund, you need to call Tesla.