Jason Garrett isn’t going to make any drastic changes to try and spark a Dallas Cowboys’ offense that has hit a level of ineptness never seen before in franchise history. Garrett shot down the notion of taking control of play-calling duties from offensive coordinator Scott Linehan, and vowed to remain true to his coaching convictions even though the offense has scored fewer than 10 points in three consecutive games. “Certainly we’re always looking at ourselves and things that we can do better, but our convictions as a coaching staff, or as a football team, really won’t change,” Garrett said on a conference call Friday. “You’re looking for different ways to implement things. You self-scout. You do a lot of different things week by week to give your team the best chance possible. But the core convictions about how you win ballgames? They remain intact.” Scoring more points is the No. 1 way to get the Cowboys to a more respectable place. Thursday’s 28-6 loss to the Los Angeles Chargers extended a level of futility that has never happened in this organization before. Not even the 2001 team had that sort of drought when the Cowboys averaged 15.4 points game (30th in the league) and rolled through a quartet of quarterbacks — Ryan Leaf, Anthony Wright, Quincy Carter and Clint Stoerner. Or the 2002 team that averaged 13.6 points a game (31st in the league) with Carter and Chad Hutchinson at quarterback.