Master Hwas Square Form Instructions analyzed and excerpted here by Sifu Jim Roach.Students do these wrong and miss the martial intent and ultimate application of the movement: The "hand has to end up in line with the curve of the elbow" as in photo 3, otherwise, it is out of position to have intent on the fingertips thus able to strike upward to the throat. These 4 photos represent movements at the end of Posture 2 and the beginning of posture 3 of the square form. I see students get the position of the elbow wrong in the 3rd photo. They do not draw in the elbow by keeping it down but allowing it to rise to a right angle, sometimes to the level of the shoulder. 
One key is the right palm becomes centered, behind left palm but IT IS ALSO IN LINE WITH THE CURVE OF THE LEFT ELBOW, then after the shift of the body forward into posture 3, we can talk about "the right elbow pull slightly down and out, causing the right hand to slide slightly to the right"