Via his affidavit, Norman basically said he heard 3 shots, the bolt action, and shells dropping on the floor above. You seem to find the later testimony's more detailed description of those basics sinister in some way. Seems natural that in testimony, the Q&A would draw out more details.
No, there is nothing basic about his statements.---- His first statement was his head was outside and he was looking up during the cycling of the rifle. He stuck his head outside and pulled it back all within 2.3 seconds. No mention at all about hearing the shells or the bolt action. He then changed his mind and gave a completely different accounting in the 12/4 Secret Service statement.
There is absolutely nothing that can be derived from his many statements other than he thought the shooter was above him and JFK was hit by the first shot
(WC: I heard a shot, and then after I heard the shot, well, it seems as though the President, you know, slumped or something, and then another shot and I believe Jarman or someone told me, he said, "I believe someone is shooting at the President," and I think I made a statement "It is someone shooting at the President, and I believe it came from up above us.").
After that it was one contradictory statement after the other. The other two members of the group believed two shots caused all the wounds. BRW thought there was only two shots and Jarman thought there was a third shot after the car accelerated leaving Dealey Plaza.