If this is a direct translation of japanese documents, the sinkings are likely exaggerated—grossly.
Note the page 108 reference to a successful attack on a Lexington Class CV. I have read other references to that, and they claimed sinking her. Dunno how many times the IJN claimed sinking those 2 CVs over the war, but suffice to say it was considerably in excess of their actual number
It certainly tells you where they might have BEEN, however.
One things seems clear to me, for whatever reason, japanese reports of their own success in both sea and air engagements needs to be taken with a lot of salt. This comes up in air ops as well, since detailed studies during limited time frames where data exists show that air to air claims for the IJNAF/IJAAF are often off by 6 times the real number (USN pilots only overclaimed by a factor of 1-2). No wonder they had "victory disease" they were systematically being fed bad intel.
