We have over 200 Excel files on a server (for different areas of the
company) that include the formula below. Our computers, by default, have the
windows date setting of M/d/yyyy (or some may have MM/dd/yyyy?). Our
organization just changed policy to avoid day/month vs month/day confusion
with dates, and now all PCs must have the month spelled out, such as
MMM-dd-yyyy or dd-MMM-yyyy.

The problem is that when a PC's system date setting is changed to MMM
instead of MM or M, the following formula no longer works. The original
intent of the formula is to identify all entries that were made in the
current quarter, and sum up the totals

{=SUM(IF(TRUNC((MONTH(A$12:A38)-1)/3,0)+1=TRUNC((MONTH(NOW())-1)/3,0)+1,F$12
:F38,0))}

Where Column A has the date the entry was made, and Column F has the value
being summed.

I used "evaluate formula" and it comes up with #value for MONTH(A$12:A38)
when the system setting is MMM, but calculates fine when using MM or M

Unfortunately, the data being pushed into column A (from a userform) may
have to segue over to MMM format as well for compliance to the policy, so in
addition to finding a way to make the formula work when the machine system
setting is changed, I need the formula to work under either system setting,
and also regardless of the format of Column A.

Our users are all using Excel 2003, on either Win2000 or WinXP.

Any suggestions would be _greatly_ appreciated!!
Thanks,
Keith
--
The enclosed questions or comments are entirely mine and don't represent the
thoughts, views, or policy of my employer. Any errors or omissions are my
own.