To add to these items, after I assign all the items in a sequence (9.1, 9.2, 9.3, etc.), they don't appear in the same order in the Today view. For instance, I have items in this order:
2nd history assignment in the sequence
2nd math assignment
1st math assignment
3rd history assignment
1st history assignment
As far as I can see, there's no way to manually rearrange these.
Note: I assigned them in Olly on my Mac, then synced with Dropbox to get them into the iPad app. They appear in the correct order in the Mac version of Today's view.