Sorry, it depends on the applicable welding standard.
As an example: D1.1 states that the costs incurred by additional NDT requested by the "owner" after the contract is signed is at the "owner's" expense unless it can be demonstrated that the unacceptable conditions are the result of an attempt to defraud or gross neglegence by the contractor. Those costs include handling, preparation for testing, testing, and the cost of repairs of unacceptable conditions discovered by subsequent NDT.
The kicker is, any unacceptable conditions detected by NDT have to be addressed once they are discovered.
Best regards - Al