Perhaps I'm missing something but
LastEdit=1284830332
-10days=1284032978
Its returning true as LastEdit is > -10 days which is what the equality asks for so it returns true. Rather than using die() you should use Debug::show() so you can output all of them and see what their LastEdited dates are. You might also what to do Debug::show($this->dbObject('LastEdited')->Ago()) so you can see (without the numbers just how long ago it is.