What you are saying is logically consistent with the facts, but is it actually true? Do we have any testimony from Chamberlain (say a diary or correspondence from that time, or a memorandum, or even a memoir), to indicate that is what happened and why? Do we even know if he ever even claimed that is what happened? Are there any other witnesses, any credible testimony? (Claiming something don't necessarily make it so. You could just be covering your ass!)

Similar claims have been made about Stalin's decision to enter into a non-aggression pact with Hitler, that he did so in order to gain time and use Poland as a buffer between the USSR and the Reich. That may be true, but then again, it may just be Soviet apologists covering for the USSR's policy and Stalin's duplicity. The point is, unless we find forensic evidence (a document we can count on being legitimate) or hitch a ride on the wayback machine and interview the participants directly, we will never know. Even if the actions of Chamberlain and Stalin are shrewd statesmanship, (as opposed to ineptness, treachery or even cowardice), it is unlikely they left any evidence of it lying around.

Did Roosevelt know about Pearl Harbor ahead of time? Did Truman really know the Japanese were about to surrender when he ordered the Bomb? Did Nixon order the Watergate break-in? Did Reagan make a secret deal with the Iranians to delay the hostage release until after the 1980 election? Did he really know about Iran-Contra? Did Dubya really know there were no WMDs in Iraq?

Nobody knows, and nobody ever will, because some things are never typed up on Oval Office stationary. Even if somebody who knew did spill the beans down the line, who would believe him if the other principals involved were determined to keep things covered up?

That's why we have historians, and conspiracy theorists.