NJ - Mercedes Benz GLE 450E $7500 ev credit Q

Hello guys,
I have a question about lease purchase. I wanted to buy GLE 450e but to take advantage of $7500, I leased it first as I was under the impression that if buy it upfront I will not get that discount. When I called MBUSA to purchase the leased car they told me that I will have to pay $2735 in penalty and pay NY state tax on the full price of the car not on the residual value. Tax amount is $6365 even though I have already paid $2900 in NY state tax when I leased the car two weeks ago. Any comments? Thanks.