Datedif question

Hello,
I tried searching the forums before posting here but I came up empty handed.

I have been using the formula below since last September without any problems; however, in the past month or so it has gotten to be a day behind (yes the pc clocks are correct).


=DATEDIF(1/1/2009, NOW()-1, "YD")*132


Instead of NOW()-1 i need NOW()-2 to get the appropriate numbers. At first I figured it was a leap year issue since the original date was 2008, so I updated the formula to 2009 and it still is not working. If I manually add up the days in the year and multiply by 132, it's not matching what this formula says.

I have tried the formula on 3 different computers using Excel 2003 and Excel 2000, all with the same results.

I also use the exact formula except with "MD" instead of "YD" and it calculates just fine.

A quick background on the formula:
I work at a hotel and we need a daily total for the year on the number of the rooms we have (132). This spreadsheet is only used the day after hence the NOW()-1.

I'm sure there are other ways to get the correct number, but I am mainly just trying to figure out why this particular formula stopped working.


Thanks in advance
~Chris