I want to set out a table below which works in all circumstances. I am using
Excel 2003:

Effective date ?

Date Interval Date Days
OVERNIGHT ? ?
1 WEEK ? ?
1 MONTH ? ?
3 MONTHS
6 MONTHS
12 MONTHS

for instance for 5/ feb 2008

Date Interval Date Days
OVERNIGHT 6/2/08 1
1 WEEK 13/2/08 7
1 MONTH 5/3/08 29
3 MONTHS 7/4/08 62
6 MONTHS 5/8/08 90
12 MONTHS 5/2/09 366

So as you can see it should take into account leap years AND must be on the
next week day if the date falls at a weekend eg 7/4/08