In fact, it just occurred to me while reviewing the vetkeys proposals that these two rows (above) appear to be out of date. The Fiduciary and II subnets are the signing and backup subnets for the various production keys, and the test subnets have 13 nodes.
I think this was pre-existing stale data in the IC Target Topology specification (rather than something introduced by this proposal). In any case, if my understanding is correct a follow up may be useful to amend this to avoid any future confusion.