Total invoice cost is what it is...regardless of what fees (other than holdbacks) there are that are added to the invoice price, the total is still what the dealership pays for the vehicle...the fees are charged to the dealership, and regardless of what you see online, they don't have to disclose to you what they pay for the vehicle...if they choose to make a smaller margin on a vehicle for you, then so be it...remember this MSRP is Manufacturer SUGGESTED Retail Price...it's suggested that the car be sold at that price, but the dealerships aren't bounded to that price...that's why they can DISCOUNT the car, AND they can MARK UP the price above sticker if they wish...
here's an example, an inventory vehicle at a dealership is damaged, let's say somebody keyed the car before it is sold. Well, the dealership has 2 choices: they can fix the damage, or sell it with the damage. Now most of us will want something off for the damage if it's not fixed (some of us think that the dealership has to give them $10,000 off MSRP to justify for the damage), but regardless of whatever happens to that car before the dealership sells it, they still paid X amount for the car, and that didn't change with the damage....if they decide to fix the scratch, then now they own the car for X + "cost of repair"....so when they go to sell the car, which most of the dealerships will want to get rid of it ASAP, they are usually more than willing to take a smaller profit margin, or sell it under invoice...heck, if they can sell that car for sticker or over sticker, trust me, they would....and if someone thinks that the only justification for them to buy that particular car is if the dealership gives them half off, then well, the dealership will probably not sell that car to that person....
Many smaller dealerships that do not have the pocket to pay for their inventory up front have banks that buy the cars for them (called "floor plan", "floor", "flooring", or etc)...think of it as consignment....the bank owns their entire inventory, and the bank earns interests on the cars while they're sitting on the lot unsold....that is why some dealerships are willing to take a short deal on a vehicle that's been on the lot for some time vs. one that just came in....the interest that the dealership has to pay for that vehicle every month is an additional fee that incurs onto their "cost" for that vehicle...but, bottom line is, just like the TDA, it doesn't matter what the dealership owns for vehicle for, to the consumer, it's what they buy it for that matters....if the dealership price is not good for you, you don't buy the car....just like if the offer you make is not good enough for the dealership, they don't sell the car....