Poor old Nishikubo-san must have been smoking the Wacky Backy when he ordered the 4 dugongs back in 2011. He then had another puff and ordered 2 more.
The only rationale must have been that Japan Airlines was going to be buried and never resurrected.
Given the trouble they have had with the JCAB getting the 330 into the air, I guess he had no choice if he wants the airline to survive in the new cut-throat low-price (no such thing as low cost) environment in Japan.
I heard that he was told by the JCAB that they would have to route test the dugong for 6 months on domestic routes as well as do their base training in the aircraft, in Japan.
Not sure how much this cancellation will cost them but it will be cheaper than the alternative.