Subtotals/Groupings
 

I have 3 columns:
Month
Product
Hours

I want to be able to group months in their respective groups and then find
the subtotal for the hours within each month group. And a Grand Total in the
end.

I am only able to do this once with the DATA / Subtotals sequence. After
that, I find that once i enter a new month in a new row, that row does not
insert itself into the respective month group. Even after I do the DATA /
Subtotals sequence from the menus.
Any suggestions how excel can refresh/update the groupings when a user
enters in a new row a given month and then for it to eventually place it in
the existing respective month group.
thanks.