Until last year when it was calibrated, it was running .9 higher than the TermLab. Since the re-calibration it has been much tighter. Scores are near to and even under the TermLab. But with any transducer, temperature, humidity, and barometric pressure will manipulate the score. Although accurate, the BnK is not the most consistent sound pressure measuring device.
In my opinion, the BnK "mic" should be retired and the "sensor" to use for world records should be the same used for world championships...the TermLab