The problem is that
1/11/08 to 30/11/08
when fully expanded reads:
1/11/08 12:00 AM to 30/11/08 12:00 AM
What we really want is:
1/11/08 00:00 to 30/11/08 24:00
which shortens to:
1/11/08 to 1/12/08
If we correct all the end dates this way and
remove all the +1's in Bob's formula, everything works.
Ron's formula now fails and it has problems
if we include odd times.