Missing IJN Carrier Class

I got the main rulebook recently, and as I was flipping through it, it occurred to me that I can’t find one of the IJN carrier classes. Unless I’m missing something, there doesn’t appear to be an entry for the Unryuu-class. The class was designed as an improved version of Soryu. Eight were planned, with three completed. An additional eight carriers of a “budget” version of the class were also planned, though none of those were completed.

Of the three finished ships, Unryuu was sunk by USS Redfin while ferrying aircraft. Amagi was sunk in port. Katsuragi suffered some damage during American air raids, but survived the war largely intact. Neither Amagi nor Katsuragi ever embarked any aircraft.

It’s true that the carriers didn’t contribute much to the war (aside from the expenditure of USN munitions). But given the number of never-finished or even “never got past the blue-prints” ships found in the book, I’m surprised that a class that actually existed doesn’t get so much as a mention in the rulebook. If a player was inclined to use one or more of them, that could be done by treating them as Soryu with late war aircraft. So not having stats for them isn’t a critical oversight.

But it is an oversight nonetheless, and an odd one. Has there been any word on why this class wasn’t included in the rulebook?