Right - it gives the illusion that you're 'getting an amazing deal and wow these people are great' when it reality you're probably getting gouged without the consulting and have to opt in for fair prices.
I frequent a local family-owned Italian restaurant/pizza place and my usual order jalapeños, banana peppers, and roasted garlic so I do a build you own. Totally fine, happy to pay the price. But one day I come in and the woman working the take-out counter sees my order before it goes in and tells me that if I order a "meat lovers", remove two toppings and sub the rest it comes out way cheaper.
So now I'm the vegetarian that always gets a meat lovers and she makes the joke every time I come in.
I don't think it's weird or nefarious that a business doesn't have completely consistent pricing and holding it differently can save you money. When we spec out services on AWS we're using the official calculator when deciding whether it's "worth it" so to us at least it genuinely feels like we're saving money.
I've seen that before, and I've also seen the opposite where people buy the veggie pizza and then add a meat or two on top to get a cheaper supreme pizza.
We had originally gone in with clever ways for owners to describe how different changes would affect the price of an item, but ended up landing on just a giant matrix where they could input the end result price for any combination. The owners couldn't articulate their own pricing well enough to model it well.