How does deduction reference work with benefit module elements

Summary:

Hi,

I would like to know how to manage the deduction reference input value for elements coming from the benefits module.

If the enrollments triggers the elements, how are we supposed to add a deduction reference without having to do this manually?

Do we need to use a formula ?

I have found the following in the user guide:

For the elements using a Benefits module that meets one of the above conditions, we suggest you use a Default reference value for all entries or use a formula to create a reference based on the Person Number of the employee or Benefits Plan name.