That is EXACTLY right.
I think you guys are misunderstanding me. Originally I wrote that He said things that *seemed* to go against the OT. I certainly do not want you to think that Catholic teaching is that He does actually do things against OT.
When He preached to others He often said things that led others to question Him because they did not understand. In those instances He clarified and then they understood. All other times there is no record that disciples left Him.
However, in the instance of His preaching about drinking His Blood, disciples still left...EVEN AFTER he further clarified it. In the past, if He was talking spiritual rather than physical, disciples understood and stayed. This time they did not stay. If He was just speaking about spiritual, they would have seen He was doing this again and stayed. But they did not. It offended them.
He even asks His disciples if what he said offended them. He knew exactly what He was saying. He was God and His Blood was very different than the blood mentioned in the OT. The OT proscribed drinking literal blood from dead animals. It has nothing to do with drinking the living blood of Jesus Christ. There is not a one-to-one correspondence between the blood of the OT and the NT. So, yes, He couldn’t teach against the OT and since these two bloods are very different things, He did not.