Color preference can be tied to payment milestones, but each milestone must be supported by objective evidence. State in the contract which inquiry, completed-sale, days-in-inventory, price-reduction, and customer-objection records must be provided, and identify the reviewer; release the corresponding payment only after the documents pass review. Splitting payment into installments without evidence conditions does not prevent decisions focused only on purchase price while ignoring turnover, discounting, and after-sales confidence. Use residual-value ranges regularly calibrated with local transaction data.
For live-order handling, see Should buyers confirm the registration date and production date?.