Let's just look at the Hosty/Bookhout statement by itself, without comparing it to anything else. In other words, let's make believe we don't know anything about "out with Bill Shelley in front." It still doesn't pass muster.
Why would Oswald designate his location as the "first floor"? It's way too big. He couldn't occupy the whole first floor. It would have been evasive to give such an answer. Since when does the FBI settle for evasive answers?
Why would Oswald cite a location without saying exactly what he was doing at the location? Real life isn't like that. We've all watched enough detective shows to know that the defendant will always say, "I was at XXX doing YYY." So, how could Hosty and Bookhout cite this huge location (the first floor) and say nothing about what what he was doing there?
And why wouldn't they have asked him why he wasn't watching the motorcade at that time? What could he have been doing that was more important to him than watching the historic Presidential motorcade? Didn't they have to ask him? Didn't he have to tell them? Wouldn't it have come out automatically and spontaneously? How could that have been left out of their report?
I really think Hosty and Bookhout twisted Oswald's words, but they did it without telling a brash lie, which they did not want to do. In other words, they protected themselves so that no matter what happened afterwards, they could not be accused of lying.
But, when they said Oswald said he was on the first floor, they (Hosty and Bookhout) were being evasive. When they said he was on the first floor but did not stipulate what he said he was doing, they were being evasive. And when they implied that Oswald's activity was something other than watching the motorcade (which was implied, as I read it) and offered no explanation as to why he preferred to do something other than watch the motorcade, they were being evasive.
Oswald was watching the motorcade at the time of the motorcade, but they didn't want to say it. So, instead of lying outright, which would have been very risky, they just said nothing.
Oswald said he was in the doorway where Bill Shelley was. And who knows? He may have used the word "doorway" or "entrance" or "steps". We just don't know. Fritz wrote down "out with Bill Shelley in front" but we mustn't assume to know that those were Oswald's exact words. He might have said, "I was out in front on the steps with Bill Shelley." There is shorthand involved in taking hastily written notes, and the Fritz notes certainly look hastily written. And you can be sure that Fritz took the notes during the interrogations because at one point Oswald said to him, "You've been taking notes; so why don't you look it up?"
Plus, it is outright preposterous to think that Fritz interrogated Oswald for many hours over two days time, and then some days after Oswald was dead, Fritz finally said to himself, "I suppose I should sit down the jot down the things that Oswald told me" as if he could retain all the details in his head. That is ridiculous.
All that Hosty and Bookhout provided was one glib statement that Oswald said that during the motorcade he was on the first floor. That is insufficient. It is lacking in substance. It is lacking in detail. It is evasive.