I have leased three Volts from Sierra Chevrolet in Monrovia CA. With the first Volt we did a "pull ahead" on the lease, turning it in two months early and getting the next Volt without paying the last two month's payments on the first car. In April we did the same thing to get our current Volt, turning in Volt #2 two months early. This time I was surprised to get a bill from GMAC for the last two months payments. It turns out Sierra didn't pay the last two months on Volt 2, leaving me stuck with paying the last two months of Volt 2's lease and the first two months of Volt 3's lease concurrently. What's up? Is that legal? Thanks!