Michael, I really appreciate the feedback.

"If you were to pick the location in America with the worst seismic events, and then use the worst possible "normal" piping arrangement, this singular chart is supposed to cover that much... and then some more."

This isn't exactly accurate. We are dealing with a client right now where seismic displacements are determined to create displacements above and beyond this table and seismic vertical settlement are orders of magnitude more than this table. This is per a soils report from a geologist. The soil is extremely poor and it is a high seismic zone.

"All our codes inevitably push some amount of "engineering judgement" onto the engineer at some point."

I agree, although in this instance I just can't convince myself this section is open to engineering judgement. It reads completely black and white to me and as a law that leaves little room for interpretation in my opinion. If this were a standard and not code adopted as law, then I would certainly pursue the engineering judgement rule here. But I'm having difficulty finding any amount of grey area as much as I think it makes sense to. Thanks again for your input!