Mine was super basic, one of many, that a 0 DAY can push an excel date a day behind, so DATE(2022, 10, 0) means Last Day of October. No need to keep an array of

Mine was super basic, one of many, that a 0 DAY can push an excel date a day behind, so DATE(2022, 10, 0) means Last Day of October. No need to keep an array of which month has 30, 31 or 28/29 days. Simple DATE(2022,3,0) gives the last day of February.