Robert, thank you for your explanation above regarding model numbers. Can you confirm that when I see model HRX217HYA on Honda's website, then see model HRX2174HYA in Home Depot, they're the same mower. I've heard too many times that manufacturers build lesser quality products for the big box stores than for their dealerships - was told by my John Deere dealership when I stopped to buy parts for the mower I purchased from them, that the BB models are different. Also concerned because the Home Depot price is $100 below Honda's MSRP. Any light you can shed on this would be appreciated.
The "K4" is the most current version of the HRX217HYA model. Honda only has the most current versions listed on its website, and to avoid confusion, drops the K-code as it rarely makes any difference to the customer. In some instances, you might see some K3s on a shelf with K4s, but that is unusual. Most dealers will discount or push the K3s out the door before putting the K4s out for sale.
All dealers and big box retailers get the exact same models made in the same factory by Honda. There is absolutely no difference in what is shipped to one or the other. There are no "Home Depot only" models made by Honda, nor are there any "not-for-Home-Depot" models either. That said, Home Depot chooses not to carry all models that you might see at an independent dealer, such as the HRC commercial mowers.
Honda sets the MSRP, but it is completely up to the retail dealer or Home Depot to set the actual selling price. This will vary from region to region, state to state, and store to store, depending on market conditions, weather, supply, etc. Generally, most new mowers sell for less that MSRP, but that is not a hard and fast rule. When shopping, do make sure you are comparing identical models and keep in mind service after the sale. All Honda dealers can provide service regardless of where the Honda mower was purchased, but often, a dealer will be more available to customers who bought a mower from his shop vs. those that bring in mowers bought elsewhere.