Question : Excel adding in error in SUM formula

Has anyone witnessed this before, or know how to prevent it.

I am running a simple SUM() formula across 2 cells. The 2 source cells are formulaic themselves. Excel seems to be adding in an error of .000000001 to the result. Ie. the result should be something like 6218.4, but it is returning 6218.400000001

When you expand the decimal points of the source, it only returns a value in the first position, nothing further on to cause the .000000001

Answer : Excel adding in error in SUM formula

In fact, to add to my earlier comment, I did find this article:

http://support.microsoft.com/kb/78113

It may explain a bit more about the issue.