Hi Guy - In regards to DNG974, the clipping occurs when the WB is changed. As shot there is not highlight clipping in sky. When the K value is changed, the sky is still blue and non of the channels actually blew-out. The blue channel was hovering ~253. The value is just low enough to trigger the C1 highlight warning (depending on the threshold set).
C1 applies an aggressive S-curve that often results in clipped highlights. With C1's highlight recovery we can recapture those "lost" highlights - but that is somewhat convoluted because the only reason they were clipped was because of C1's S-curve.
When I open the same files in RAW Developer, what was clipped in C1, usually is not clipped in RAW Developer. The delta in this case is that RAW Developer opens with a linear tone curve. If we select the "Linear Response" in C1, then the two editors are more closely matched.
Judging a camera's approximated DR with C1 and the default tone curve can be misleading. If I was batch-processing 800 images, then I'd just roll with it and not worry. But if processing a smaller group of images and there is time to tweak individual files, setting the response to Linear and applying your own S curve in the Curve panel will generate better results.
After looking at your P30+ files, I think I'd be more excited about a P30+ sensor integrated into a ZD camera body!