Since v3.0, Sword of the New World has reduced its default character slots in the family quarters from 15 to 4. The accompanying bug is that existing families that have only 15 slots are also affected. So a family with 7 characters would have 7/4 instead of 7/15.
See more in the forum discussion. Just for comparison, the default slots for sGE is 9.
Update: See the new policy regarding default quarter slots in Quarter Slots on Newly Created Accounts forum topic.