Microsoft is working to fix a bug in Excel 2007 and Excel Services 2007 that involves calculations numbers around 65,535. Microsoft is blaming the bug on the function in it that takes the value and formats it to be displayed on the screen, not on Excel's calculation engine itself.
Excel is calculating the values correctly, according to Microsoft, but the function in it that takes the value and formats it to be displayed on the screen is faulty.
The bug was introduced when Microsoft made changes to the Excel calculation logic in the Office 2007 time frame, according to officials.
As Excel Group Program Manager David Gainer explains, the Excel bug affects a very particular set of results in 12 cases:
"There are 6 floating point numbers (using binary representation) between 65534.99999999995 and 65535, and 6 between 65535.99999999995 and 65536 that cause this problem. You can’t actually enter these numbers into Excel directly (since Excel will round to 15 digits on entry), but any calculation returning one of those results will display this issue if the results of the calculation are displayed in a cell. All other calculation results are not affected."
No ETA on when Microsoft will issue a fix for the problem. Stay tuned.