Software Upgrades and Inventory Remediation

I'm in the process of upgrading different versions of Microsoft Office in our environment where the Installed Software by Computer report lists some inconsistencies (e.g. can show both versions of Office for a computer or even found one with Standard and Professional listed).  Can anyone explain this mix of Office versions; especially with the one that lists Microsoft Office Standard 2007 and Microsoft Office Professional Plus 2007?

I have a full s/w inventory running once a month and deltas each week.  Should the deltas resolve the inconsistencies or do I need to wait until the fulls are run?