in the operator’s CASA-accepted and audited ops manual
They just accept the ops manual, they make no determination that the information contained there in is correct, particular with respect to aircraft information. Flew for an operator whose V1 take off data compiled in a ready use cockpit chart, and in the ops manual, guaranteed you would crash following a failure at higher temps if you elected to go following failure at, or after, V1. Chief pilots who write these things don't necessarily know the subject matter about what they decree. Cast a very jaundiced eye.