The update columns shows the difference between the UR of the Organization and the application (on the deployment server I think, assumed to be the same on all servers since that is the only supported configuration).
So if you use Get-CrmServer, that tells you the version of the server, and Get-CrmOrganization tells you the information for the Org.
I guess someone cleverer than me with PowerShell may be able to parse those out and show one if they are the same and both if different, perhaps.
Hope this helps.
Adam Vero, Microsoft Certified Trainer | Microsoft Community Contributor 2011
UK CRM Guru Blog