Service pack deployments are handled differently than patch deployments. Since Microsoft recommends that a service pack be applied before all patches, will not allow you to deploy service packs and patches in the same deployment. It is because of this behavior that when you select Deploy All Missing Patches, it literally means to deploy all missing patches; no service packs will be included with this operation.
Deploying to a single machine
To deploy the latest service pack to a single machine, select a machine from the scan results, right-click it and choose Deploy Patches to { machine name }... > Latest Service Pack....
You can perform the same operation by choosing Machines > Deploy Patches to { machine name }... > Latest Service Pack... from the menu bar.
Deploying to a group of machines
To deploy a service pack to a group of machines, first select the desired service pack from either the 'Machine Summary' or the 'Summary by Patch', followed by clicking on the 'Missing' tab at the bottom of the Patch Info window. CTRL or SHIFT select the machines you wish to deploy the selected service pack to, right-click and choose Deploy by Machine > Selected Machines.
You can perform the same operation by choosing Machines > Deploy by Machine > Selected Machines... from the menu bar.