How are you handling off-cycle performance documents?

We are looking for recommendations or design approaches for managing off-cycle performance documents in Oracle, such as probation evaluations or one-year anniversary evaluations. Currently, there is no functionality to use relative dates (only fixed dates) within the performance templates. For example, we would like to configure a standard performance document to be due within 60 days of probation end date and have each task assigned a set number of days for its due date. Since employees are hired on different dates and have varying probation periods, our HR team are manually adding the task due dates after