So, I am guessing that I could go the commercial bank I use, ask to see the manager and tell him to secure an account for Dollar (or my local Fiat) cost averaging and it would be a great idea? Or perhaps I go to see a seasoned broker and explain to him about his help on managing a dollar cost account and they won't see it as weird right?
Either, whichever you think will work for you. But in general, DCA means that whenever you have money either fix or not, you're ready to invest into the market. And what you'll do is to buy Bitcoin after all. Regardless of where it is going to come from, commercial bank or broker or from your pocket, you do what you have to do and that's to become consistently buy Bitcoin. That's the whole point why you hear people telling others to DCA so that they'd get Bitcoin.