Override Participant Effective Date

Good Afternoon ~

I am hoping you can help me with this or point me in the right direction. We have 3 officers who started on 7/1. 

Contract agreements allows for their benefit coverage is effective as of date of hire (7/1/19). I have done the overrides for their coverage and rate effective dates for all plans except imputed income (when I tried overriding that one, the rate changed to something like 10 million dollars a month, so I removed the override).

Any suggestions on how to best accomplish this? This is not something we do very often at all.  The last time we did this it was like 2014 I think.  No documentation to be found on how we accomplished it.