That would imply Aurvandil has brought it's full might to bear, and not instead, left a considerable chunk at home. We don't need to send our full mobile army to deal with Barca, that would just be needlessly expensive in terms of equipment repair.
The scary part:
There's a good chance that he's not bluffing. There's 29 nobles in Rettlewood. That leaves 25 more unaccounted for. Assuming a similar CS to noble ratio, there could be another 25k CS or so out there.
