What they forget to mention is that Allen's customer most likely had a rate higher than 4% in 2007 and was close to paying it off. That is until BMW talked him into getting a new car for the same payment for another 5 years.
I dont get how this is any different than someone who never had a BMW walking into the dealer and buying a car for invoice and getting 0.9%. That rate is offered to anyone who is eligible, isnt it? They dont have to be a repeated customer to get it.