I'm not sure I agree with you, although I've never done an in depth study; I have however leased over 2o cars in my short life. What I do is take the negotiated monthly lease payment and multiply it by our sales tax rate which is and ahs been the amount paid monthly. Maybe, if you have a not so honest dealer (that would be most of them) who quotes you a price inclusive of taxes, then you could be right because there would be no way to sort it all out. It's very hard to beat these guys at their game.

This is only my 4th car but I'm 99% sure I know how it works - when the leasing company pays taxes for you, they don't do it for free, they charge you APR for it. So, normally, they take a total amount of taxes due, say $3000 and add it to your cap cost. Then the lease is recalculated to amount for that extra cost. This is how it worked with my previous cars (non-BMW). Now with BMW, the total came out higher by a few percent of the tax amount. I couldn't get the actual answer from a dealer other than they use a program and that what it gave them. It could be dishonest dealer but I really don't think so. More likely BMW financial services adds some percentage on those payments. It could be that their process is diffrent from other manufacturers, I honestly don't know.