conditional formatting behaving differently on Mac vs Windows

So I've got an excel doc with some simple conditional formatting set up and it works perfectly on my Mac. However, it doesn't work exactly the same for my co-worker, who is on Windows...

I have just two rules set up:

rule 1: If the cell in column 'O' contains "n/a", I want it to shade the entire row gray. My formula is: =IF($O1="n/a",TRUE,FALSE)
rule 2: If the cell in column 'O' contains a date of today or any day prior, I want to shade the entire row red. My formula is: =IF(ISBLANK($O1),FALSE,IF($O1<=TODAY(),TRUE,FALSE))

I have the applies to field for both set to: $A:$P

The conditional formatting works perfectly on Mac - if 'O' is "n/a" the row is gray, if 'O' is a date <= today the row is red, if 'O' is blank or a date > today no special formatting is applied (and it looks that way - plain black font, no fill color).

It mostly functions the same way on Windows - if 'O' is set to either "n/a" the row is gray, if 'O' is a date <= today the row is red...But if a row is gray or red and I change the value of cell 'O' to either blank or a date > today, only cell 'O' is returned to plain black font and no fill color - all the other cells in that row remain either red/gray. Why isn't this returning the entire row to the non-formatted state (plain black font, no fill color)?

I've also tried rewriting my conditional formatting formulas like so to see if it would help, but it had no effect:
=($O1="n/a")
=AND(NOT(ISBLANK($O1)),$O1<=TODAY())

FYI here are the versions we are running:
Mac excel version: Microsoft Excel for Mac 2011 Version 14.0.0 (100825) (running on OS X 10.9.4)
Windows excel version: Microsoft Office Excel 2007 (12.0.6718.5000) SP3 MSO (12.0.6721.5000) (running on Windows 8)

So, any ideas? Thanks in advance!

Originally Posted by etaf

its working fine for me in excel on windows 2013 version

I dont think 2007 should have an issue - i can try later when i get to the 2007 PC

thanks for checking! looking forward to hearing your results with 2007 version...thanks!

Originally Posted by etaf

BUT if i copy down then the format seems to change to just the cell
because the range is added to and only the cells copied

is that what you are doing ?

No, I'm simply hitting the "delete" key in the cell containing the date, which makes the cell blank with no formating - but the rest of the cells in that row keep the prior formatting. Or, I'm simply changing the date by manually typing it in - again only that cell goes to blank formatting, the rest of the cells in the row keep the prior formatting.

Originally Posted by etaf

you then get a range to apply to of
=$A$1:$S$9,$O$9:$O$13

see the change

have a look ar the applicable range in your formatting and see if its still
just $A:$P

Yeah, the applicable range is still $A:$P...

It was originally created on Mac Office 2011. Starting the sheet again would be a pretty arduous task...There's hundreds of rows and lots of columns...Damn!