FormationSet_S<NN>.tbl records are slot lists -- 1 + 8*FrameCount fields,
exactly. Resolving every squadron's FormationID and comparing gives
sum(n) <= FrameCount holding 1159/1160 across all 28 stages, 0 unresolved, with
539 filling the formation exactly. The single violation is a debug leftover
(S20, AI_Test / MessageSet_test, Formation_1_only with n=2) and is recorded.
The old 'n is not the _NN suffix of FormationID' observation was right but drew
the wrong conclusion: the suffix IS FrameCount, so n=9 against _30 just means 9
units in 9 of 30 slots.
Also: FormationID does not hash into its table (0/16). FormationSet carries a
name roster record -- no FrameCount, fields are (tag, name, '') with the tags
being the record keys -- the same convention as Enumerate_Squadrons. Second
occurrence of 'keys are resolved by an in-table roster, not by hashing'.
Does not close the 387-vs-300 gap, and the key derivation stays open.
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