Piper is consistent about the time he saw Oswald. From his WC testimony:
Mr. BALL. What time was it that you spoke to Oswald and said you thought you would have your lunch?
Mr. PIPER. Just about 12 o'clock.
Lunch was from 12:00 to 12:45pm so it makes sense it was around this time.
Piper takes his lunch around 12:00pm so he can be fairly confident about the time.
James Jarman makes this point in his affidavit on the 23rd:
"The last time I saw Lee Oswald on Friday, November 22, 1963 was between 11:30 a.m. and 12:00 noon when he was taking the elevator upstairs to go get some boxes. At about 11:45 a.m. all of the employees who were working on the 6th floor came downstairs and we were all out on the street at about 12:00 o'clock noon"
As Oswald was seen/heard by the men coming down from the 6th floor he must have went up there sometime between 11:30 and 11:45pm. At least fifteen minutes before Piper goes for lunch.
The problem is, if Oswald has come back down to the first floor around 12:00pm then he's not up there when Givens says he is and there's no way he can sneak past Williams having his lunch to hide in the SN.
What it boils down to is whether or not to believe that Piper was correct with the 12 noon time.
Reasons to doubt:
1. Other employees have stated that they normally break for lunch about 10-minutes or so before noon to wash up, etc. And that on 11/22/63 they broke a little earlier than normal because of the motorcade.
2. Piper also said that when he heard the shots he looked at the clock and it was 12:55 pm.
3. Piper also said that it was about 1:00 pm when the police made them vacate the building.
4. Jarman said that LHO went up between 11:30 and 12:00.
Your reasons to believe:
1. Lunch was from 12:00 to 12:45pm so it makes sense it was around this time. [Do you really think that Piper normally continued to work on his own while the other employees normally broke for lunch about 10-minutes before noon (and a little earlier than normal on this date?]
2. Piper takes his lunch around 12:00pm so he can be fairly confident about the time. [ this is redundant, so see my comment on #1]
As Oswald was seen/heard by the men coming down from the 6th floor he must have went up there sometime between 11:30 and 11:45pm. At least fifteen minutes before Piper goes for lunch.
The problem is, if Oswald has come back down to the first floor around 12:00pm then he's not up there when Givens says he is and there's no way he can sneak past Williams having his lunch to hide in the SN.You are assuming that Piper didn't typically break for lunch when the others normally did. There is simply no evidence that supports your assumption.