Kommentar zu Könige I 22:52

In the seventeenth year of Yehoshofot. Some wonder about this verse, because it is stated concerning Achov that he reigned twenty-two [years],²⁴Above 16:29. and concerning Yehoshofot it is stated, that he became king “in the fourth year of Achov,”²⁵Above v. 41. thus resulting that Achov’s [rule] ended in the nineteenth year of Yehoshofot[’s rule], but here it states that Achazyahu became king in the seventeenth year of Yehoshofot[’s rule]. However, I searched and found in Divrei Hayomim concerning the kings of Yisroel, that [Scripture] is not exact in the number of their years, and if one became king at the end of a year, he counts it at the beginning, but he does not count it elsewhere. Therefore I say that, “in the fourth year of Achov,” that is mentioned in reference to when Yehoshofot became king, does not count with it Achov’s first year [of kingship]. And so you find in the majority [of cases]. Also, the year in which Yehoshofot became king is not included in these seventeen years.