What I get with this code is May 2021. Are you getting May 2020?

Did you press F9 with the entire code selected after inserting it?


Did you read the introductory material in the tutorial? It is important.

The following gives me May 4, 2021.
{ Date \@ "MMMM d" }, { = { DATE \@ yyyy } + 1 }


I do not understand the 160 in Paul's but am guessing it has to do with a 360 day accounting year.
In general the math for a year is much simpler than for month and day.



Paul is a regular here and will likely explain all.