Just beacuse this fellow was involved in that meeting doesn’t mean much. It is very likely that he heard this from someone with a strong “anti-army” bias who just made it up or gave an estimate without any investigation. The question should be posed to the person (Rosh Yeshiva or otherwise) who quoted those numbers “is that based on a real study?” “”How many of those were already OTD before they entered the army?” “How does your source define OTD? If they change the type of yarmulka they wear, would that be defined as OTD?” Was this an independent study that is likely conducted without bias?
My guess is that if there were a real documented, professionally conducted study on this topic, we would have heard about it by now.