The man who could have been the key to Chris Brown's demise is not entirely backing the District Attorney ... saying it's possible Chris waxed the floors at a Virginia Children's Center as part of his probation even though he never saw it happen.
TMZ spoke with Neil Cobb -- who says his statements to the media were taken out of context when he was quoted as saying, "Chris never helped me do floors at the Tappahannock Children’s Center."
Cobb says Chris never cleaned the floors IN COBB'S PRESENCE ... but it doesn't mean he couldn't have done it some other time.
"He mighta did floors ... but he didn't do it with me," Cobb said ... adding, "I never said the guy didn't do his community service."
We broke the story ... the D.A. claims Brown may have lied about completing all of his community service ... but Brown's lawyer Mark Geragos says the accusations are a load of crap.