If we go back to the airport to retrieve a box and take it to the hospital:
The time field names are unhelpful
a pick up time from the hospital is inappropriate.
If we name the time fields as "hospital collect" "airport deliver/collect" "hospital deliver" things would be clearer.
If we have a value in "hospital collect" and no box numbers it is an error
Implies that with no box numbers the appropriate time field can be blank. Normally, this would be the "hospital collect" field but it could be the "hospital deliver" field.
If we go back to the airport to retrieve a box and take it to the hospital:
If we name the time fields as "hospital collect" "airport deliver/collect" "hospital deliver" things would be clearer. If we have a value in "hospital collect" and no box numbers it is an error Implies that with no box numbers the appropriate time field can be blank. Normally, this would be the "hospital collect" field but it could be the "hospital deliver" field.