I think we can agree that Williams was unreliable and saw more than he would tell. I suspect he was up there, with his lunch. Remember that was originally widely announced as the assassin?s lunch. Williams originally tried not to be associated with the 6th floor at all but would have to change his story over time as he quickly realised he would have to account for the police likely finding his prints on the bag and bottle. Also he likely surmised that someone might have seen him up there also, I believe Rowland did. So he then did the next best thing and tried to be on the sixth floor much earlier than the 12.15 timestamp provided by Rowland for the gunmans presence.
Jarman and Norman tried to claim he went up with them to the fifth but they eventually had to recant before the WC. They provided evidence that their trip upstairs occurred after 12.22 and ties in nicely with Brennan observing those two after 12.24.
My take, for what it's worth, Mr Crow----------------
----------------Mr Givens ate the 'assassin's lunch' that morning (see Mr Shelley on this!)
----------------Mr Rowland's simultaneous sighting of Man A (black, east window) and Man B (white, with weapon, west window) tells me that Man A and Man B were conspirators---- Man B must have been v. relaxed about Man A's seeing him with a weapon!
----------------Mr Arnold's sighting has to be explained away by DPD, FBI... enter Mr Williams, who will change his story as per evolving instructions, up to and including eating chicken-on-the-bone sandwich (!?)
----------------It's
possible, I think, that Mr Williams was held up on 6...
Incidentally! I also think Mr Piper may have wandered up to 6 at the wrong time too.
His account of his own doing around motorcade time just don't add up IMO. (& Why was he rather pointedly asked in his Warren testimony if he'd gone higher than 4 that day?) V. mysterious!