I want a report to show only the patches missing on particular machines and or machine groups. Ideal want this automated, scan machine / machine group, that report showing missing patches gets sent. Mostly I want to avoid seeing the installed patches as I found a report that shows the missing patches but they are scattered among the installed patches. Also I can do a manual scan and export the missing patches list to a csv.
If you want to schedule a scan only that shows missing patches only. You create a new Scan Template and choose to only show missing patches. This scan template along with the Condense Patch Listing could be a good match for what you are looking for.
You could also create some ad hoc reports to show missing only by using the Use Advance Filters option.