C. F. Keil and Franz Delitzsch on 1 Chronicles 24:4

1Ch 24:4

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. 1Ch 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 people, the fathers'-houses, i.e., the groups of related families comprehended under the name בּית־אבות, divided themselves further into individual households, whose heads were called גּברים, as is clear from Jos 7:16-18, because each household had in the man, הגּבר, its natural head. הגּברים ראשׁי are therefore the heads, not of the fathers'-houses, but of the individual households, considered in their relation to the men as heads of households. Just as בּית־אב sa tsuJ .s is a technical designation of the larger groups of households into which the great families fell, so הגּבר is the technical expression for the individual households into which the fathers'-houses fell.