A few things in those panels.

First, I think this was a direct response to when Loeb originally insinuated that Supergirl was stronger. A lot of people didn't like that (I sure as hell didn't), and so they crafted a response that would work within the constraints of what was explained earlier. That said, if this reveal was always intended to be the case, then more power to Loeb.

Second, I didn't pay much attention to it at first, but the part when Superman says "[his] parents," and then "not... Jor-El and Lara," that kind of goes back to what we've discussed in concurrent threads about how this particular era's Superman seemed to like to undercut his Kryptonian heritage.

And finally, I'm not sure why Superman wondered out loud if Kara was being powered by her ship's solar panels. I thought that when they first found the ship, they already came to the conclusion she was powered by them during her journey to Earth.