Excel 2008 : Chart Not Updating (based on random data)

I have an Excel:mac 2008 worksheet that has randomly generated data. Two charts are connected to this data. Calculation is set to automatic. However, when I click command-+ (the F9 equivalent for mac), the data changes but the charts do not update. There are some other strange elements. (1) Sometimes, if the chart is highlighted, the chart redraws for the first re-calculation, but not for any additional recalculations...and the 2nd chart remains unchanged. (2) Sometimes, the Excel file will update the chart on its own quite some time after the multiple recalculation attempts---I've seen it happen in an inactive, yet visible window at least twice.

I encountered this problem 6 months ago, sought a solution, found none and set it aside. Now, I need these "animation" style charts for my stats lectures, and I can't get them to work. I've tried searching the various help forums for about an hour...and I'm getting nowhere. Any help finding a solution would be much appreciated.

I have attached a small file that should serve as an example.

For what it is worth, I recently transitioned from PC to mac and at that time, from Excel 2003 to Excel 2008.

Kind regards.