The object of this second enumeration of the Levitical families (compare 1 Chronicles 24:26-27 is also curious. It brings the number of families up to twenty-five, which is one more than we should have expected.
SDA Bible Commentary (limited)
Volume 1-7
20. Rest of the sons of Levi.Verses 20-31 give a second enumeration of the Levitical classes (see ch.23:7-23). The object of this second listing may be to designate the heads of the families at a different time. The list begins with the Kohathites, but omits the Gershonites (see ch.23:7-11).