The sons of the priests made the ointment This is added to show, that though the Levites were intrusted with the keeping of this ointment, yet none but the priests could make it. Over the things made in the pans Was to take care that fine flour might be provided, that when occasion required they might make cakes in pans.
Related Commentaries of 1 Chronicles 9:30
1 Chronicles 9:30-31
30 And some of the sons of the priests made the ointment of the spices.
31 And Mattithiah, one of the Levites, who was the firstborn of Shallum the Korahite, had the set office over the things that were made in the pans.