I actually have an updated version of that formula, which I think takes care of a couple of odd issues when adding months to a date that results in the end of February. Probably doesn’t matter for your use case of adding a full year, but if you ever use it for adding months, then I would recommend the new version instead. (I should update my original post)
You could also consider using the EDATE Excel formula in the Excel Formula plugin. Not sure how well it works, but something to try. I think you would use a formula like this.
=EDATE(A1,12)