"Date modified" by a human (i.e. user)?

Hi y'all.

Ok, so I have this process in our instance that counts the days the opportunity is in each sales stage:

Working fine and dandy. However, the Opportunity record is updated every day by the Sugar Admin user in order to add 1 day to the appropriate count field. A manager wants to see when the record was updated by a human (his sales staff) but cannot because of this process. Any idea for a workaround?

Thanks,
KGM