How do I get this formula to work?
 

OK this may be a long discription but hopefully you will understand it.
I work on attendance, inputing students hours, this is how the spread sheet
is set up

On the left of the sheet are the names of the students 1-80 rows, on the
top are the days in months from june 6th till now going across from left to
right, directly below the month colums are the spaces for the days to input
the total hours, directly to the right of that info going from top to bottom
left to right are the total hours, scheduled hours and percent attended. The
total hours and percent attended have their own formulas of course.

This is the formula I was trying to use:
=IF(AT2:AW80<=3.0,AZ2:AZ38+12

Now if all of that made any sense, PLEASE,PLEASE,PLEASE, I want the colum
with total hours, which lets say are 60, to add 12 every week 60, 72, 84 e.c.t
If any of that did not make sense I will re-write this again till I get it
right.
Thanks again,
Mystical