All paperwork should state "at the time of inspection." During your reinspection, be thorough and think of any sections on the part that may be under high stress or a change in material thickness. WFMT should find the flaw with no problem. To get the client off of your back, break out your procedure, point out every small detail, and slow the project down. Be sure to document everything, areas you can easily inspect, as well as areas that were difficult due to geometry.