Ignore the 400 points for a moment.
Throughout the OT, we have seen many different archetypes for fleet formation. From double ISD I at the shield gates to ISD, quadruple Raider and Arquittens in Thrawn. In the clone wars, the Republic had a standard: Each general commanded 3 Venators.
So in the OT, what is in your opinion the standard fleet archetype (Mostly considering imperials,since rebels are a mix-match of everything at all times)