I have stated in other threads that Fredo was lying to Michael even in the boathouse scene when he claims he didn't know it was going to be a hit.

His story just does not hold up. He claims Johnny Ola told him Michael was being "tough on the negotiations," and there would be something in it for him if he could ..what? Use his brilliant negotiating skills to change Michael's mind? Don't think so. I think it was more like "make sure those drapes are opened."