ASSUMPTION

This function is not documented and simply found by trying. Hence, this entire documentation is assumed.

Void Handles.Playbacks.PreviousPage()

This function does not fully work as Avolites never intended these buttons to be paged.
Handles.Playbacks.PreviousPage() ) decrements as expected – but you can go down to page 0 which probably isn't intended.

See also http://forum.avolites.com/viewtopic.php?f=20&t=5846:

The next and previous page functions unfortunately do not work properly for workspace windows as they attempt to loop around the maximum number of pages. For the playback faders this is 60, so when you are on that page pressing next page will take you to page 1 and the opposite is true with previous page. However workspace windows do not have a predefined maximum page number so this is set to zero which means that next page always loops around to page 1 and when on page 1 previous page will take you to the maximum page which is zero. One work around is to set the page directly e.g.:

Handles.Beams.ChangePage(Handles.Beams.Page.Index + 1)

Note however that this doesn't do any error checking so will allow you to go to any page number including negative page numbers.

Pages - Change Pages:

  <macro id="adb.Macros.PreviousPagePB" name="adb Change Page PB -1"> 
    <sequence>
      <step>Handles.Playbacks.PreviousPage()</step>
    </sequence>
  </macro>