I am creating automation rules based on preventive maintenance (PM) schedules for my team. One type of our systems receives quarterly PM tasks performed to it every three (3) months and a more-involved annual PM task performed to it every twelve (12) months. This essentially amounts to the first three PM tasks performed are quarterly PMs, while every fourth PM is the more-involved annual PM.
Creating an automation routine for the quarterly PM has been quite simplistic: triggered by an issue transitioning to a 'Done' status, and meeting other conditions, a new issue is created with the due date set for {{now.plusMonths(3)}}. This allows for the next-scheduled quarterly PM to regularly be created every 3 months from the completion of the previous PM.

My thought-process on handling the annual PM scheduling is to trigger a similar automation routine, albeit with the additional information required for the annual PM, every 4th time the aforementioned automation routine is executed.
I am having trouble realizing this thought as an actual automation routine. Is my thinking flawed and a better solution exists?
TLDR; I want to modify the actions of an automation routine every n time it is executed to perform slightly different actions.