I co-owned Hughes Auto Parts, Inc. for over 40 years. We were distributors that services 5 states and parts of others. In the U.S. it is illegal for any company to require a customer to use a particular brand of product over another as long as your chosen brand meets or exceeds the Society of Automotive Engineers products. Harley-Davidson, Ford, GM, Chrysler, Kubota and the names are too numerous to list have lost law suits leveled against them for demanding a customer pay exorbitant prices for their branded filters, lubricants, etc.
Remember, Kawasaki, Kubota, Kohler, Briggs-Stratton or any other motor company makes filters, belts, hoses, batteries etc. They purchase them with their names labeled on them and set the specifications for each item they want to use in the manufacture of their machinery.
You can purchase from any filter manufacturer and have your label and boxing on them. I had three brands specific to our territories and our filters exceeded all manufacturer's specifications. Each of the manufacturers tried to talk us out of exceeding the auto, mower, motorcycle, truck or other manufacturer's specs because of the cost. However, when introducing an aftermarket brand, you better have something other than price to sell.
At any length, all any of you need to be sure of is the specifications are there. You can cut a filter apart (not that expensive if you want to check them out before you put the filter into service) and check out any claims by the seller. Such as anti-drain back valve, relief valve, micron paper, cotton, etc.
Not many folks wants to buy your mower so they'll generally provide the product you're purchasing.