new dilema

example

Columns A B C D E G H
03/03/04 03/04/04 2 03/04/04 03/06/04 3 4
03/04/04 03/06/04 3 3

I have my first column directing the appropriate days of
payment -- but I have a new dilema - if I put this formula
in my second column for additional service different
place - I duplicate a date by adding them - is there a way
to get my column H to recognize if column B and D have a
duplicated date of service ? This is the only way to get
the total months pay to come out right -

Thank you

Katherine