That's why the number of games is what the stats are based on, not seasons. Mahones has played 81 regular season games, and Josh has played 78 games—almost the same.
And as I said, there are a lot of variables and ways you can read and interpret stats (see Mark Twain, "There are lies, damn lies, and statistics"). I do agree, style-wise, that Lamar is a better comparison. The point here is he fumbles too much, no matter what type of plays are being called.