I understand that this is a small sample size, however, this is a measure of efficiency. It's relative.
Here's their definition of the stats:
"Team efficiencies are based on the point contributions of each unit to the team's scoring margin, on a per-play basis. The values are adjusted for strength of schedule and down-weighted for "garbage time" (based on win probability). The scale goes from 0 to 100; higher numbers are better and the average is roughly 50 for all categories. Efficiencies update daily during the season."
While the sample size is small, we can still conclude that this team is inefficient thus far. This team will not maintain it's current top-10 AP ranking if they continue to perform this inefficiently throughout the season.