Hosting Plans tab provides the information about Hosting Plans that use the application version. You can view and edit the Hosting Plan properties by clicking on the plan name. In this case you are redirected to the Billing Director - Product Manager. Here you can add new applications and view all the applications installed.
Upgrade options for a Hosting Plan are the same as for a single package set.
However, Hosting Plans sample, i.e., the list of Hosting Plans displayed in popup window for selection, is different. In this case, you will be offered to select Hosting Plan(s) that include at least one package set from available ones. Again, you can select a particular package set to be included in Hosting Plan(s) selected for upgrade (special drop-down menu provided).
To add a new (not upgrade) Application to a Hosting Plan, please go to the Billing Director - Product Manager - Hosting Plans.