Amazingly enough, you don't actually have to make a change, force a sync, and see it. When you make a change to the Class Structure format in Jamf it displays a preview, so you can see what the data in each field is. Just don't save. 🙂
Unfortunately the Period number is not one of the fields that the PS plugin has, so we ask our teachers to drag their classes into Period order.
I don't seem to have a link to the latest v1.3 of the PS plugin but this is the link to v1.2, and there is no difference in the roster query.