I interpreted the question differently, and I'm pretty sure that yours is the more useful answer.
BTW, I got a copy of --- I think --- "The Red Planet" from Netflix the other week, and I was shocked to see that it was a single-layer disc. On the other end of the spectrum, the Wookie Groomer DVD-9 of the TESB split-screen was so loaded with data that it kept causing my cheap Norcent player to glitch.