Okay, so, again, what does Dive-X make that is "expedition grade"?
My experience is both limited and purely anecdotal. But, in my very limited experience, it has been the PTBs that make my BT not "expedition grade" (even if it had the required range). And I know for a fact that I'm not the only one that has had these exact kinds of issues with the PTBs in a BlackTip.
Which is basically what I was saying earlier. I wouldn't call the CudaX "expedition grade" even if you think it has adequate range to qualify for the term. There is literally NO "expedition-qualifying" quality control on the PTB batteries.
Also, I suppose, nowadays, one could make an argument that, to qualify as robust enough for "expedition use", you might require the scooter to support charging without breaking the seal on the hull.
Even if you use a vacuum system to test it every time you close it up, an O-ring that is opened and closed repeatedly is going to have a greater chance of failure during a dive than one that is sealed up once and left that way.