Cleansing in the 12th and 18th Year

Question: 2 Kings 22 and 2 Chron. 34. How are we to reconcile the cleansing in the 12th year and in the 18th year? H.
Answer: Both are true; and both speak of the cleansing which in Josiah’s eighteenth year followed the discovery of the book of the law in the house of Jehovah. But 2 Chronicles alone adds the account of his earlier seeking after God ten years before, in the eighth year of his reign and the twelfth beginning to purge.