Before deciding how to allocate the pre-shipment inspection cost, use the inspection standard and the organization performing it to judge whether the conditions are in place, then assess the risk with the acceptance responsibility defined in the contract and who pays for re-inspection and corrective action. There is no single answer to who pays; the key is that the contract states the inspection standard, the performing party, the re-inspection conditions and the corrective action responsibility. Keep the inspection standard and the performing organization and the acceptance responsibility defined in the contract on one versioned master sheet; when who pays for re-inspection and corrective action changes, update the record before signing.
The pre-shipment inspection fee has no fixed payer; both parties should agree it in the contract. Pair your first trial order with What proof should an exporter provide before requesting final payment?. Inspection fee estimates should note the quote date and exclusions; the actual cost follows the contract, invoices and local confirmations.