The plausibility is basically nil and this is a very good example of the kinds of intellectual sleight-of-hand that Greg makes often in his videos, where he strings together a few common assumptions and then presents them as an explanation to inconvenient facts. In doing so he also implies that he has reasonably intimate knowledge of the subject matter and that he is a reliable source in-and-of himself. It is cleverly disguised editorializing.
Greg presents a few assumptions here that may or may not be true. There are no sources cited and those assumptions are never called into question.
Greg's explanation is as follows as to why the IJAAF only reported two losses that day;
1. The IJAAF was more concerned with pilot losses than aircraft losses because of the underlying narrative that the axis powers were defeated through largely the attrition of their pilot corps. He further implies that by 1943 the IJAAF pilot situation was considered rather dire while their aircraft supply was considered relatively plentiful. No thought here is given to what the IJAAF believed about itself at the time nor to the specific situation in New Guinea. While pilot attrition overall has an immeasurably large impact on the course of the air war, he presents no evidence that the rate of pilot attrition in 1943 was of great concern to the IJAAF, or that the IJAAF even considered that it had a pilot shortage by Oct. 1943 when the Kearby mission occured.
2. Likewise he claims that aircraft losses might not be mentioned in loss-reports amongst IJAAF because the aforementioned pilot shortage because the loss of the aircraft is immaterial to the loss of the pilots, and that because the Japanese had a surplus of aircraft to pilots (another one of his assumptions) that they would not report the loss of the aircraft in cases where the pilot is recovered. This assumption only makes sense if you do not think about it. First and foremost one of the overarching themes of the Claringbould books is that a lot of Japanese aircraft were destroyed on the ground in comparison to in the air, and he apparently uses Japanese records to substantiate losses from strafing and bombing attacks.
In order for Greg's assumption to be true, we have to assume that the IJAAF in New Guinea had a vast surplus of planes already in-theater and that the losses of those planes never generated any need to request to high command that replacements for losses be shipped in. Also if we are using Claringbould as a reference, then we have to accept the fact that the Japanese reported their material losses on the ground, but somehow only chose to report their material losses in the air if it resulted in the death of a pilot, and only a high ranking pilot.
3. Which gets us into our third assumption, which is that the IJAAF treated its lower ranking pilots poorly, and therefore would not report their losses. I do not think that there is any evidence of this whatsoever. It makes no sense from a logical standpoint; how would a theater commander request pilot replacements etc without reporting their losses to higher command?
Basically in order for this theory to be true, we just have to assume that the Japanese had no functional chain of command, and no real military bureaucracy. Furthermore we have to accept that authors like Clarinbould, Dunn, etc have never considered this alternative explanation to the apparent juxtaposition of kill claims vs loss records. This also means that we have to ignore the whole entire body of scholarly work in the European theater as well that substantiates similar trends of over-claiming, or that we need to consider kill claims made by P-47 pilots as uniquely credible in comparison to their peers in different aircraft types.
