Tesla's chief executive, Elon Musk.Noah Berger/Reuters Tesla’s chief executive, Elon Musk.

The announcement on Tuesday by Elon Musk, chief executive of Tesla Motors, of a hybrid lease-purchase plan for its Model S electric luxury sedan, coupled with a guaranteed buyback program for three-year-old cars, generated a great deal of Internet buzz and a lot of armchair number-crunching.

Until now, it has not been easy to lease a Model S, partly because it was not possible to claim alternative-vehicle tax incentives unless the car was purchased outright. So in conjunction with Wells Fargo and U.S. Bank, Tesla has come up with a purchase plan that resembles a three-year lease. Tesla says the 10 percent down payment will be covered, in many cases, by federal, state and local tax credits or rebates, and the company promises to buy the car back after three years if the customer no longer wants it.

Mr. Musk says he is putting his own money behind the cars. According to Tesla’s news release, after 36 months of ownership and loan payments, owners “have the right, but not the obligation to sell your Model S to Tesla for the same residual value percentage as the iconic Mercedes S Class.” According to Kelley Blue Book, the residual value after three years of a Mercedes-Benz S Class – which Mr. Musk cited as being comparable to the Model S – is 47 percent of the price when new.

Mr. Musk has also guaranteed that if the Model S is worth more than that in three years, he will personally buy the cars back at their higher fair market value.

In making its announcement, Tesla said the new program would give customers a Model S with the bigger 85-kilowatt-hour battery pack for an “effective monthly cost” of $543. But that figure is based upon a number of assumptions, including whether the buyer lives in a state with large electric car tax incentives, like Colorado; that the buyer will claim tax deductions for using the car for business purposes; and that time that might have otherwise been spent at a gas pump is worth $100 an hour. Tesla’s calculator factors in money saved by not using gasoline, but not the time spent charging the Model S.

Confused? So are others. A headline on The Atlantic’s Web site said, “It would take a rocket scientist (literally) to come up with something this crazy.”

Crazy or not, the stock market seemed underwhelmed by Mr. Musk’s creative financing. After rising earlier in the week when Mr. Musk promised, via Twitter, a significant announcement, Tesla shares fell 7.3 percent on Wednesday, to $41.10,  after the details were revealed.

Basically, the new financing plan consists of a 66-month car loan with 10 percent down and a 2.95 percent interest rate. The monthly payment for an 85-kilowatt-hour model should be more than $1,000 per month, but Tesla’s payment calculator will change that number to less than $500 if you check the right boxes. Then there’s the buyback option, which changes everything.

So will the new financing plan – which seems to be a hybrid between a car loan and a lease – be a win for the buyer or for Tesla? Opinions vary. At Business Insider, Sam Ro compares the deal to a put option, declaring it a win for the customer. But Nelson Ireson, writing for Motor Authority, posits that there’s an $873 difference between the projected value of a three-year-old Tesla and the amount a buyer would still owe on the loan. The difference he came up with doesn’t work out in the customer’s favor. (Then again, for someone who can afford a car that costs more than $60,000, what’s another grand?)

At Slate, Matthew Yglesias has a different take on Tesla’s confusing combination of its out-of-pocket loan payment calculator and creative buyback offer. He sees it as a roundabout way for Tesla, its customers and its affiliated banks to divide a tax credit. But there are other views on that. Johnny Lieberman at Motor Trend doesn’t share Mr. Ygelsias’s opinion that the tax credit is equitably distributed.

If you’re still bewildered by all the numbers and ways of looking at this, perhaps Marek Fuchs, from Yahoo Finance, can help you make sense of everything:

After all, lay everything you know about Tesla end-to-end and it may still be hard to reach a conclusion.

By BENJAMIN PRESTON