As per my knowledge, it has sent out offers for all viable internal applicants. Anecdotal evidence suggests that this also rings true for external ones, but alas, with only a small N known to me, no significance can be claimed. I believe some Nuffield offer holders would reject their place and enable the college to accommodate other candidates, thus more Nuffield slots could be on the way in either scenario. Moreover, DPIR is a rich department compared to other social science counterparts in Oxford, they have various fully-funded options for DPhil candidates (though not everyone), so stay tuned!