[Geoff Bacon]

I don't know how you are trying to add the extra pages but the following should work

1) Copy the file to a local folder on the the tablet
2) in MS, display the original song name on a collection or SetList or Songs page
3) Long press the original song until checkboxes appear
4) "Edit song" on top menu
5) Tap "Files" (2nd tab, Fields is first)
6) Tap "big plus" and choose the 2 page pdf
7) Edit the page order to put it in the correct place e.g. 1-12, 42,43, 15-41 (assuming 13 and 14 being replaced)
8) Crop the new pages as required

Geoff
PS I've never had the need to do this but it should give you an idea of how to do it.