If you are looking to save money on car ownership, leasing is the most ineffective way to go about it. I would imagine one price leasing is even more inefficient than the typical monthly scheme. The specific question you are asking would be highly dependent on the leasing contract, so it is impossible to answer. In order to make it equitable for the buyer, there should be some provision for an early lease termination regardless of the reason.
Presumably you have the cash to pay an upfront lease, so you have the cast to buy a car outright. Buying a gently used 3 year old (at least) car with cash is the best way to save money on car ownership.
The biggest cost in car ownership is depreciation. With leasing, you are not only paying the depreciation but also financing it. With up front leasing, you are probably ending up with an even worse deal. By buying a three year old car, much of the depreciation has been already paid, and if you own that car a long time, the depreciation per month becomes rather negligible.
If you are really wanting to save money, buy an even older car. Almost all of the depreciation would be paid, the cost will be low, sales taxes and licensing fees would be low. I like to aim for cars in the 4k range. Even with repairs these cars typically have a far lower cost of ownership then buying nearly new.
It all depends on how much you hate money. If you really hate money, then lease.