Split transactions by percentage
Each split line now carries a dollar amount and a percentage, both always visible. Type either one and the other is recomputed. The percentage is an input aid only — the dollar amount is the only value that is stored, and no line is ever silently rewritten. When rounded percentages miss the bank total the balance box shows the gap and the user fixes it by editing a dollar amount. A small change to the split UI built in PRD-74 — everything else about splitting is unchanged. A cashbook is either GST-registered or not — those are two genuinely different states (the tax column and GST maths only exist for GST cashbooks), so they're two separate prototypes, not one with a toggle. Pick the one you want to review — each is the full end-to-end flow.
Split by percentage — GST-registered
Split lines carry Amount and % plus a Tax column; amounts are tax-inclusive and the panel shows the derived GST. Percentages are of the GST-inclusive bank total.
Open prototype → Non-GST cashbookSplit by percentage — non-GST
No tax column, no GST anywhere — Description · Account · Amount · %. The simpler flow for cashbooks that aren't GST-registered.
Open prototype →Why two prototypes?
Prototypes contain only what we want built — no demo-only toggles. When a feature behaves
differently across a known condition (here, GST registration), each state is its own prototype, so
the dev team knows exactly which screens exist to build. See
PROTOTYPE.md and the system decision log
(docs/design-prototype-system/DECISIONS.md · D12).