Yea thats pretty much how it goes, if you think they are lying but don't have proof you have to doubt. Sometimes though the "truthful" face throws me off because usually if they are telling the truth they look dead at you and their eyes don't go all over the place. But some of the people still look all over the place even if they are telling the truth. I'm thinking about trying out the the black and white option like MTT said to see if it makes a difference.