I came up with the below calculation which seems to work, but when my duration has a decimal (.5 days, 1.5 days) the calculation doesn't notice the .5, it rounds down to day.
Example:
Handoff date - 12/19 10 am
Duration - 1.5 days
Calculation - 12/20 10 am
Thoughts on how I get the system to notice the decimal??
valueexpression=ADDWEEKDAYS({handoffDate},({plannedDurationMinutes}/480))
textmode=true
valueformat=longAtDate
displayname=Due Date