Charles Ellicott Commentary 1 Chronicles 25:31

"for the four and twentieth to Romamtiezer, his sons and his brethren, twelve." — 1 Chronicles 25:31 (ASV)

An analysis of the whole list shows that the first, third, fifth, and seventh places fell to the four Asaphite guilds, or clans; the second, fourth, eighth, tenth, twelfth, and fourteenth to the six guilds of the sons of Jeduthun, or Ethanites; the sixth, ninth, eleventh, thirteenth, and the remaining ten places, to the fourteen guilds of Heman.

It appears evident that all the lots were thrown into a single urn, and that the Asaphite and Ethanite names were all drawn, as the chances made it likely, before the Hemanites were exhausted. As it happened, only Hemanite names were left after the fourteenth drawing.