Keep in mind the reporting date was of no significance to Chris Johnson. He doesn't get FA after this year anyways so unless he was holding out for a week just to report and then do it again next year, it was entirely expected.
That does mean he is more committed to his holdout than a player that just has one year left on his contract though. For a one year guy, the team can make a "we wont franchise you" concession and the guy will sometimes cave. Here? They wont franchise him 'cause he has another year after this one. I also think he knows he wont have another season like his 2k year so he wants the big bucks before anyone starts asking if he's washed up, if it was his Oline, etc.