When using date range run parameters in merge actions, the correct values depend on the datatype of the date field being compared:
Date fields: You typically need to enter one day earlier and one day later than your intended range. This ensures that all records within your desired dates are included, since date fields do not store time information.
Datetime fields: The exact dates you enter will be included because datetime fields store both date and time.
Understanding the datatype of your field is key to configuring run parameters correctly and avoiding missing records. This distinction should be noted when documenting run parameter usage.