no you're not missing anything.    your cleaning cost might be alittle high( depends a lot on cleanout, and how a person is storing the cleaned seed, and treatment cost is going to be the same whether you are treating your own beans or purchased seed ).     but what some are missing is that most companies offer some performance guarantees, (free replant)  if you replant are you going to have to pay $18 all over again?

harry stine and co. are smart people, keep that in mind.