I was making a guess based on the VIN-- as I had a S85 order in October (December delivery) with a VIN over 27000. All same options but leather instead of 21"-- works out to $81k after rebates.
The formula I used was Tesla's, 1% month/ $1 mile. Tax credits here total $10k-- so the "ceiling" on price is different here. So while you might laugh at my number, I think it's reasonable as I could indeed buy a car similar to yours-- but an S85-- for only $6k more... brand new.
I don't mean to offend. Please don't misunderstand. Heck-- I'd consider your car if it were closer and little less!
I'm just offering my perspective as a potential buyer who has already done the math on a new S85 (and decided to wait on the MX pricing).
I do see a lot of MS listings... but a listing is not a transaction price or a sale.
I fully expect Tesla to not remain immune from depreciation forever.
You are smart to upgrade now, while you can do so with essentially no money lost-- assuming you get your price... and I hope you do!
It really is a stunning car... and I know an owner local to me who would agree.
Tesla Supercharger - Somerset, PA - YouTube