Yes, I always enjoy these a-ha moments when there is a difference between an author's methods and your own, and you discover what specific parts of their method need to be modified to adapt to your own way of working. And you can do this without faulting the author, you just don't take that part of their advice "because it doesn't apply".
I like polyglot's explanation of the idea that 5 two second exposures, given "Barry Thornton's way" might not equal a single 10 second exposure. (There's intermittency effect too, but light bulb warmup is more significant in this case).
So, assuming you pass a sheet of cardboard over the test strip exposure, your method really gives a single 10 second exposure when you proof (at 10 seconds) so your print exposure will be a single 10 second exposure.
I'll assume you don't have a fluctuating-light-output (fluorescent bulb) type enlarger, these make the synchronizing of test exposures and print exposures less certain... That's what I have, in my case I need to be mindful of whether my 10 second exposures on my test strips got the first or the last 10 seconds of a 40 second exposure...