Exactly. That's what I have been thinking.
First of all, we still haven't seen any memos. Secondly, did he share these memos with anybody? Thirdly, just because he wrote memos after the meetings (if he did) who knows if they are truthful? It would still be a "he said, he said" situation. Unless there were tapes available.
He might be writing what he thinks he recalls. Feelings.....
However, I know a businessman that keeps a dated Journal record of every phone conversation of significance .... It was actually subpoenaed in a case as evidence. ..and accepted as such since it was dated and consistent.....
Of course that's not a “memo” .....rather a written account.