If you have any issues with your BSS exam there is an option to contact the BSS office and complain. This can initiate , as in my case and if they feel it is warranted, a visit from one of their chief examiners .
In my case, which is still ongoing at the moment so I don't want to elaborate to much, I purchased my boat with a cert. which became due for renewal in Sept. The exam bought to light issues that obviously should have been picked up at the original exam and some that could have happened since.
My case is still in the process but believe me once you complain they really do a thorough job.
Newf