Gus isn't the goalline back. Dobbins was getting most of the goalline/short yardage work over the 2nd half of the season when he established himself in the RB roation whereas Gus had one TD of less than 3 yards over the last 8 games of the season.

Where they use Gus is more as a 'closer' taking advantage of tired legs in the 4th quarter of games once they've already built up a lead. That's what his role was when Ingram was the lead back and for the most part that didn't change that much once Dobbins worked his way into the lead back role over the 2nd half of the season. That's certainly a significant factor in its own right, but a little different than saying Gus will get the goalline/RZ work when one of the biggest factors in the 2nd half surge from the Ravens was establishing Dobbins as the lead back and a RZ weapon.