The process flow follows:

This is a basic IF statement; If this is true, enter..., if not then do
this...
=IF((+K9+O9+S9+W9+AA94),"Not Eligible",
This part of the formula checks to see if the total of the cells listed is
greater than 4.
If it is then the text between the quotation marks is entered into the
parent cell.
If the total is not greater than 4 then it will perform the second condition.

The second condition in my formula is another IF statement, and follows the
same rules as the first IF statement.
IF(ISBLANK(AC9),"",
If the cell is blank then enter the text between the quotation marks; in
this case the cell is left blank. If the cell is not blank then go to the
next condition.

IF(OR(AC9="A",AC9="D",AC9="NA",AC9="MSG",AC9="NIS" ),
Again an IF statement, following the same rules...
For this part of the formula there must be text present to get the desired
result.
The formula checks to see if the text in the cell is equal to any of the
text, listed in the quotation marks, before moving on to the next step.

IF(AD9="",NOW(),AD9),"")))
Yet another IF statement...
For this part, the text condition from the previous step was checked; if the
text matched the time (NOW Statement) will be entered in the cell. If not
then the text between the quotation marks will be entered. Again, in this
case the cell is left blank...

Remember these are logic based questions...
If ( ) is true do "this", if not do whatever follows the comma...

As for your issue of refreshing check your formula for consistency and the
security settings. Hopefully this answered your question...