At n2k16 David Vasek pointed out that FFS partitions on 4K disks are

At n2k16 David Vasek pointed out that FFS partitions on 4K disks are
created with far fewer inodes than DEV_BSIZE devices.

Scale the default 'density' value by (sector size)/DEV_BSIZE to
create the same number of inodes. Obviously a NO-OP on DEV_BSIZE
devices.

Thanks David!

ok deraadt@