@propduffer
As far as I can see, if they were to throw out the April 8th receptions, that changes nothing.
Actually, by disregarding the April 8th ping detections then it actually resolves my main concern about the acoustic detections, that is the distance between the 2 days' detections was too far for the expected detection range.
This makes it more likely that the signals are from an ULB, and if so that it is located to the north west region (near the 2hr 20m long sequence of detections). This is also the area NOT search by the AUV.