In the first 13 games, Dak took 424 snaps from under center: 322 of those plays were runs, while just 11 were passes (no real drop-backs) and 80 were play-action attempts. This means the Cowboys ran the ball 78.3% of the time they lined up with Dak under center.
Compare that to the last two games: the Cowboys have run 71 plays with Dak under center, but only 47 of them were runs (24 passes or play-action attempts). In those two games, the Cowboys have only run the ball 66.1% of the time that Dak has been under center – this is much less predictable that the 78.3% over the first 13 games.