[masraum]

I'm no expert. While I think the info in the first link that you posted does show that there are differences between the 2 (looks like the viscosity is actually a little different, but like I said, I'm no expert), I suspect that the bigger difference may be in the additive package, the amounts of thinks like calcium, phosphorous, Zinc, and Moly. I also didn't see the oxidation index which I think is another key characteristic.

These charts below show a comparison of unused/virgin Driven DT40 and DI40 oils. The "DI" is for direct injection vehicles and has reduced calcium, I believe.