How to Default HSA coverage amount for Loss of Dependent eligibility

We have a requirement to align the HSA option with the Medical option. we have used a default enrollment formula to automatically drop the overage children.

Incase of a single child getting dropped, HSA and Medical are correctly dropped to Emp only option, but we are not able to return the coverage amount.
Default enrollment formula returns the 'PREV_PRTT_ENRT_RSLT_ID' which brings the previously elected amount, but we want to return amount based on the
logic. The documentation for Default formula does not mention about returning the coverage amount. Any Help on this is Appreciated.

Thanks !