1 Chronicles 24:4

“And there were more chief men found of the sons of Eleazar than of the sons of Ithamar, etc.] Or heads of men, heads of their fathers’ houses and families: and thus were they divided; among the sons of Eleazar there were sixteen chief men of the house of their fathers, and eight among the sons of Ithamar, according to the house of their fathers; in all twenty four, and into so many classes or courses did David divide them; Jarchi says at first when the tabernacle was at Shiloh, there were but sixteen courses, eight from Eleazar, and eight from Ithamar, as is explained in the treatise of fasting f104; but when David saw that there were more heads of men, or chief men of Eleazar’s, he divided…”

“there were more chief men found--The Hebrew may be translated, "There were more men as to heads of the sons of Eleazar." It is true, in point of fact, that by the census the number of individuals belonging to the family of Eleazar was found greater than in that of Ithamar. And this, of necessity, led to there being more fathers' houses, and consequently more chiefs or presidents in the former.”

“more: Ch1 15:6-12 sons of Eleazar: Num 25:11-13 according: Ch1 23:24 1 Chronicles 24:5”

“As the sons of Eleazar proved to be more numerous in respect of the heads of the men than the sons of Ithamar, they (David, Zadok, and Ahimelech) divided them thus: "For the sons of Eleazar, heads of fathers'-houses, sixteen; and for the sons of Ithamar, (heads) of fathers'-houses, eight." הגּברים לראשׁי means neither in respect to the number of the men by the head (cf. Ch1 23:3), nor with respect to the chiefs of the men, divided according to their fathers'-houses (Berth.). The supplying of the words, "divided according to their fathers'-houses," is perfectly arbitrary. The expression הגּברים ראשׁי is rather to be explained by the fact that, according to the natural articulations of the…”