Report Builder question - Mfg Days calculation

What is the best formula to use when calculating 'Manufacturing
Days'. I have several reports that I have written that each has a
huge amount of formulas. I'll bet there is an easier way.

I need to create a report that figures the average number of order
requirement by due date for the past, present and future for many
customers. I have to subtract out the holidays taken and proposed,
they cannot be included in the average.

Figured for each column: $'s, hours, #lines, #pieces for: 2 fiscal
months in the past, 1 fiscal month in the past, 1 week in the past,
current week, 1 week in the future, 2 weeks in the future, 3 weeks in
the future and YTD average.

Wish me luck, and please tell me what formulas you would use. Feel
free to email or contact me offline. amfab@... 574-264-4431

Thanks!
Ann Rohyans
AMFAB