Dealership response 
We are aware someone has marketed the structure you mentioned .We’ve received a lot of overflow requesting it .
My gut after 17 years with Mercedes says a dealer had a few loaners where they could do these discounts and have now run out of cars. We believe this started in TX and spread fast. We’re getting calls now from NY and Iowa.
I believe they do not have the inventory to honor that offer and now we’re getting the influx of requests. We do not have cars that fit that structure . We have one 2022 left. It has less than 3000 miles and its more likely we sell to someone local who has not been exposed to that deal, that no longer has the units to back the ad. Our offer is 10% off any EQ model we have in stock plus any incentives someone may qualify for .
If your search does not bring you a car , we still have ours at 10% off, 7500 lease , 2500 electric bonus , 1000 star access (if you can prove you qualify ) & MF=.00234. Good luck in your quest.