Matthew Poole and continuators on 1 Chronicles 26:17

17 East-ward were six Levites , north-ward four a day, southward four a day, and toward Asuppim two and two.

For that being the Chief Gate of the Temple required a better Guard.

i. e. The house of Asuppim, as it is called v. 15. where also it is said to be on the South-side; on which there seems to have been a double Guard both belonging to Obed-edom, v. 15. one at the South-gate, and the other at Asuppim; where possibly the Sacred Treasures mentioned v. 20, &c. were layd up, and therefore a particular Guard was necessary. See on v. 15.