You are technically correct, yes. However, the problem is that even after going over this specific section, its not entirely clear what kind of carrier the Japanese have in this battle. Its vaguely implied that its possibly the same carrier that escaped damage in the Battle for Midway in 1941 (meaning it could probably be a fleet carrier), but Turtledove doesn't elaborate more than that. Moreover he doesn't give much of a hint about the escorting force either. So I lot of this is filling in gaps in a reasonable way.
In this case, I believe the Japanese would not send the same carrier force to this battle... especially a force that, after a year, would choose not to reinforce it with another carrier. It doesn't make sense to me that this force would operate a carrier by itself when it has all the time and to get reinforcements. In this battle from the book, I decided to slightly modify the force by giving the Japanese 2 converted light carriers to face off against 2 US escort carriers (this is different from the US one escort carrier vs. one un-defined IJN carrier from the book).