Confirmed to be a Security Update for Microsoft Office products
Information of update here : http://support.microsoft.com/kb/2910902
Update is intended to patch a security hole in Excel that allows remote code execution.
Additional information here : https://technet.microsoft.com/library/security/MS14-083

In any case, I am unsure how to get excel's ActiveX buttons to work AND have the update at the same time.
Please note that I have done a system restore to an earlier date, and installed ALL pending updates except:
KB2910902 - Excel Security Update
KB2553154 - Office Security Update
KB2899519 - Word Security Update
It has not been confirmed if a system restore is required, or if you may simply uninstall the listed updates.
I have reached an acceptable solution, and as such, have stopped messing with it. I will hope that MS can provide additional information on how these updates function so that users can repair the spreadsheets.


Please note these are tagged as 2010 updates, but the linked article shows that 2007, 2010, and 2013 products are affected.
Updates may have different affects on other products. I am only able to confirm for 2010.