Hi, am I right in thinking you want the day-4days as a reference date, unless it is before the 4th of the month then use today?
A simpler expression to try for the date:
will return today if the day is <= than the 4th, or 4 days ago if it is after.
So the 5th would return 1st feb.
Put this into a variable and use that as the date to refer from in the expression
Is this what you need?