Well in most cases yes. But you have to remember that the DOT [b]does not[/b] overlap. So let's say that you shoot your enemy once with a headshot, then wait for the DOT to go to work. Once it runs out, one more body shot and DOT will clear the target. So technically OP is right, but when would this ever happen?

If there is a short break between the first and second shot then they are dead in two.

This