Explicit user-assumption scenario, no verified taxes/FX/profit forecast. Default simple model: cnyToTargetRate, targetCurrency, shippingPerUnit, feesPerUnit, targetGrossMarginPercent. model=resale additionally requires purchaseQuantity (whole listed packs, 1-100000), packagingPerUnit, customsPerUnit, taxPerUnit, returnsReservePerUnit, fixedOrderCosts, platformFeePercent, sellingPricePerUnit, targetContributionMarginPercent (replaces gross margin). All allowances must be explicit, including zero; percentage rates 0-99.99 with at most 2 decimal places. Resale requires a whole piece/pc/pcs pack and CNY listing price; assumes every purchased piece sells. Reports breakdown, break-even prices/units and scenario profit; missing inputs are unavailable.