With the greatest respect to Ajahn Chah and Ajahn Boowa... I would never be comfortable in calling anything they say Buddhavacana. Even those who are purported to be arahants do not speak in unison on certain issues. Consider for instance Ajahn Chah's dismissiveness of much of the Abhidhammic and commentarial material. Contrast this with some of the Burmese masters, for example.
Who to believe as definitive Buddhavacana? Why open that Pandora's Box?
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine