It’s not because there is more than one variable (MF for example) and even your supposed single variable is ambiguous.
Is it 15% off with or without dealer cash? You will assume one interpretation, the manager will assume another.
You can repeat this “there’s only one variable” affirmation to yourself as many times as you want to but payments are going to vary wildly because you left it open to interpretation and there are multiple ways to structure a lease while nominally showing a 15% discount on paper.
Gaslighting is a common tactic sales people use to undermine shoppers. We have even seen online brokers outside of LH flat out lie to people, saying that Rate Findr is not accurate and that only THEY have realtime leasing data. It’s sad to see the extent some sellers would go for their own financial gain.
To your point, I was asked to step in to help a family friend with a car, she was working with a “regular” nyc based broker, who, she told me, was saying things like “you’re putting me in a bad spot with my dealer, they’ve been holding this car for me for you for days” when she hadn’t even agreed to numbers yet, and then he went on to berate her once he found out she was working with another broker “why would you waste my time and my dealers time, you’re really hurting my business and my relationships with my dealer here having them hold cars when you’re playing games, I don’t even think that deal is real but we can come down another 20 bucks a month if you can come in today”.
The truth is, the “average” broker is nothing more than another dealership experience if you give any resistance to their proposed deal, pressure, gaslighting, and suggestions that other deals are not possible.
Sales rep seldom have a say in pricing. They “always” need to check-in with their manager first. That’s part of the process. Do I like it? Nope. That’s why I negotiated my last 3 lease deals via email and phone.
Problem solved. Most sales managers will either say yes or no to your offer without wasting your time.
Honestly emailing is hit or miss for me. Got a great deal emailing for my gmc truck. Looking for a luxury car for my wife had more luck going in person.
Twice I’ve been told that the manufacturer web site is wrong.
A Toyota salesman told us that the configurator on Toyota.com was wrong, and that it wasn’t possible to get tan interior with red exterior. This dealer had two red cars in stock, but both had gray interior. We bought a red/tan one elsewhere.
[And before we left we got cornered by a sales manager, who approached us waving an invoice in his hand (lol). He then pretended not to know what TDA meant (it’s “Toyota Dealer Advertising”), but he was absolutely certain that the fee had to be passed along.]
More recently an AutoNation BMW sales manager told me that bmw.com was wrong and needed to be updated, and that the rate for 36 months on a CPO was 3.99%, and not the 2.99% that the manufacturer advertised. I bought a CPO elsewhere days later, financed at 2.99%.