Unto the reign of David - It is not quite clear why this clause is added. Perhaps the writer is quoting from a document belonging to David’s reign. Or, he may mean that some of the cities, as Ziklag 1 Samuel 27:6, were lost to Simeon about David’s time.
Related Commentaries of 1 Chronicles 4:31
1 Chronicles 4:31
31 And at Bethmarcaboth, and Hazarsusim,l and at Bethbirei, and at Shaaraim. These were their cities unto the reign of David.