Most of the time, you're correct. But coming back from the edge of Klingon space, we go from McCoy saying "at least we're moving again" to Carol Marcus running to the bridge to Sulu getting a reading he can't understand. That's not much time and a cut doesn't make sense anywhere in there.The simple fact is, we don't know how much time passes to get from point A to point B.
I know, I know...McCoy might have made his statement hours after they zoomed off at warp. But, if that's the case, why does it take a ship three times faster hours to catch the Enterprise at warp?
It's just poorly thought out.