I did say implicitely....which means it might just be how I am inferring it. Here's the whole section pertaining to Command Variants, but pay particular attention to S8.362 and S8.367:
S8.36) LEADERS, COMMAND SHIPS: Leader variants (CWL, DWL, CC, DDL, etc.) are designed to lead squadrons of similar ships; there will never be a squadron consisting entirely of leader variants because this would mean that other squadrons had no leaders. See (S8.64), which prohibits "allied squadrons". See exception (S8.48).
(S8.361) A second (third, fourth, etc.) leader ship of any given type cannot be included unless all other such leaders are accompanied by two "combat variants" of the same basic hull type. For example, you may have one D5L if you wish, but if you want two of them, there must be two other D5s in the fleet (following the first D5L).
NCAs are CAs (and can be freely mixed with CAs in squadrons led by CCs), not leader versions of CWs. CCHs are CCs, not leader versions of CCs.
CLs and CWs can be mixed in squadrons.
DDs and DWs can be mixed in squadrons.
Fast Cruisers are considered to be cruisers of the equivalent type and can fill out CA squadrons.
Scouts, Commando ships, Minesweepers, Escort, Survey ships, Tugs/LTTs without battle or carrier pods, PFTs without heavy weapons, and other support ships are not "combat variants".
(S8.362) No leader ship can be included unless all larger leaders have their supporting ships. For example, an F5L cannot be included in a fleet with a D7C and a D5L unless the D7C is accompanied by two other D7/6 combat ships and the D5L is accompanied by two combat D5 hulls. The ISC, being under separate PPD limits (E11.17), is exempt from (S8.362).
(S8.363) Dreadnoughts are not "leader" ships; however, see (S8.331). Carrier groups (S8.31) are separate from the leader/led provisions of (S8.36); they lead their escorts. The fleet flagship is exempt from the leader/led provisions of (S8.36) but could lead a squadron; the Klingon force in (S8.362) could have a D7C as a flagship.
(S8.364) The Federation uses the "L" designator for plasma-armed ships. These are not "leaders" within the context of this rule.
(S8.365) The Kzinti Super Space Control Ship (R5.24) and any similar units published in future simultaneously counts against the limits of PFTs, carriers, and size class 2 ships.
(S8.366) Jindarian asteroid ships may serve as fleet flagships but are otherwise not included in the "squadron" organization concept.
(S8.367) A standard (non-leader) warship can lead a squadron including standard (non-leader) versions of the next smaller class. For example:
FFs (but not FFLs) can lead police squadrons.
DDs or DWs (but not DDLs or DWLs) can lead Frigate Squadrons.
CL/CWs (but not leader versions thereof) can lead DD/DW squadrons.
CA/NCAs (but not CCs or CCHs) can lead CW/CL squadrons.
(S8.368) Hydran fusion and hellbore ships can be mixed in squadrons within a given class. A war cruiser squadron could include a Horseman, Traveler, Mongol, and/or Tartar. Similarly, the Romulans can mix squadrons of KR, Hawk, and Eagle series ships.