Formula across several pages

I need help in writing a formula(s) that will pull a count from multiple pages. There are 151 employees, and each person has their own tab.

Emp 1, Emp 2, Emp 3, Emp 4 - each work a different shift ( 1, 2, 3, OSI). They have 16 hours sick leave (SL), 8 hours vacation (VA), and 8 hours FMLA. My report page shows that for everyone that worked on shift 1, there was 8 hours of sick time. Shift 2, 8 hours vacation and 8 hours of sick leave, and 8 hours of FMLA.

What formula will work? Does it need to be two formulas?

Right now I have to list all 151 employees in a formula like this-
=SUM('ALDERSON M'!$C60, 'BLODGET P'!$C60, 'BRADFORD T'!$C60,'CHANCE J'!$C60, 'GATES J'!$C60, 'GATES R'!$C60,'GOODWIN M'!$C60)
For each event (SL, VA, FMLA. This isn't all) It is so time consuming keeping up when someone changes a shift.

In the Attachment, the box X2 (OSI), is the box where the shifts will be changed. Then, each month will have their own counts too.
I know this is confusing, but any help will be appreciated. I only can attach a photo. If you want the file, I can send it to you.

Thank you for any help you can offer,
LeNor
EXCEL 2010, Windows 7

2014 time usage.jpg

Maybe you want to consider attaching the actual Excel file.

Thank you Glen,
On the report page I have listed the page for OSI. As you can see, the formula that I have been using has to be changed manually as the person changes work areas. Some of the pages have up to 21 pages in the formula. I would like this to change automatically depending upon what is put on each employees page in box X2. The report page is just one of 17 report pages. There is one for each area. If I can get help with one, then I can fix the others.

On the report page, I have changed the January column to reflect this file with the formula I have been using. The other months still contain the original formula. It's altered a bit since I copied and pasted the page into another workbook.

I usually can figure formulas out, but this one has totally stumped me.
Any help you can offer will be greatly appreciated.

Best regards,
LeNor Reese

Hello,

You can use the SUM function to add up all the same cell between 2 worksheet!. There is no limit
EX: =SUM('EMP 1:EMP 4'!C36)

this will add up all values in cell C36 in on worksheets between EMP 1 and EMP 4 included.
If someone leaves you just delete the worksheet or add one for a new employee. As long as they are between the 2 worksheets you specify it will add them up.

Hope this help