Budgeting delay costs for a car import means breaking it into tasks you can accept against, covering at least the destination port free-time and charging rules, the document arrival and clearance plan, and a contingency for inspection or document amendment, with a named deliverable owner. Get the free-time period and fee schedule from the shipping agent, work backwards through original document arrival, declaration and vehicle release, and keep the delay contingency as a separate line in the budget. Note the destination port free-time and charging rules in the order file and attach the basis for the document arrival and clearance plan; pause the next step if the inspection or document amendment contingency changes. When finished, have the person responsible for car import storage fees sign off, record the date of the documents used, and note any exceptions that must be cleared before the next step.
Demurrage and storage free days are not standardized; they can differ by shipping line, terminal and voyage. To build a checklist, refer to How do port delays affect China vehicle export orders?. Storage and demurrage estimates should state the quote date and exclusions; actual costs follow the contract, invoices and local confirmations.