One claim and one journal per financial year.
The home-office GST treatment depends on the business structure — a sole trader claims the GST share, a company doesn't. Set the entity type in Settings, then come back to start the claim.
Only the cashbook owner can change the entity type.
PRD-85 state. Existing and imported cashbooks start with entity_type = null (nullable, no backfill). The calculator blocks with this gate until the owner sets the entity type in Settings → Accounting, because the GST branch (sole trader vs company) can't be chosen without it. Mirrors the GST-not-registered gate. Do not silently default to sole trader.