Information about how Microsoft updates the 2007 Office products

Microsoft has updated how they are using update packages in Office 2007 System:

With the 2007 Office system, each update rollup package is cumulative regarding the whole Office program. Therefore, if you apply an update rollup package to a 2007 Office product, you apply all the fixes that are contained in that update rollup package. This includes all the fixes that are contained in each earlier Office program update rollup package.

For example, you apply an update rollup package that was released May 22, 2007, to Microsoft Office Word 2007. In this situation, you receive all the fixes that are contained in that rollup package as expected. However, you also receive all the fixes that are contained in the previously released rollup packages for Word 2007.

From this MS KB
http://support.microsoft.com/kb/949370

See the MS KB for more info.