1. The invoice amount shall be 100% of the contract amount. If a foreigner wants it, just issue him a proforma invoice and fax it to him. Just type a proforma invoice on the computer with a piece of stationery. It has nothing to do with custom. The invoice provided to the customs at the time of customs declaration must be in full.

2. It doesn't matter how many times you apply for write-off, but a contract only needs to be written off once. You can't write off the money that should be written off before you receive the last payment.

As long as there are customs declaration forms, verification forms and invoices, there is no problem with tax refund.