Contradiction with Numbers 4:3
It lists the age for Levitical service as from 30 to 50 years old, while Numbers 3:30 may imply leadership without specifying age.
Numbers 4:3: From thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.
Contradiction with Numbers 8:24
It sets the age for Levitical service starting at 25 years, contradicting any interpretation of Numbers 3:30 suggesting a different age for service or leadership.
Numbers 8:24: This [is it] that [belongeth] unto the Levites: from twenty and five years old and upward they shall go in to wait upon the service of the tabernacle of the congregation: [to...: Heb. to war the warfare of, etc]
Contradiction with 1 Chronicles 23:3
It states that Levites were numbered from the age of thirty and upward, which could be at odds with other passages setting different age criteria for service.
1 Chronicles 23:3: Now the Levites were numbered from the age of thirty years and upward: and their number by their polls, man by man, was thirty and eight thousand.
Contradiction with 1 Chronicles 23:24
This verse changes the age of Levitical service to 20 years and upwards, contradicting previous age requirements such as any implicit one in Numbers 3:30.
1 Chronicles 23:24: These [were] the sons of Levi after the house of their fathers; [even] the chief of the fathers, as they were counted by number of names by their polls, that did the work for the service of the house of the LORD, from the age of twenty years and upward.