Frank, you're correct with what you're saying, only if you cut the 4ball, however, this hit is more of a "full hit" sending the cue ball through the 4ball and avoiding the possible conflict with the 6ball (but not by much) The cue ball will end up near the top left corner, Rodney drew a line that was (imo) not the direction the cue ball will take, imo, the cue ball will be tracking straight toward the top left pocket, be careful with the speed of this particular shot. This shot is felt through the cue ball, not the object ball..playing a good cue ball is the crux of this option in terms of succeeding, a good cue ball will give you the best chance of prevailing because there's really not much room to play your cue ball through, but doable.
This shot is all about the cue ball, by eye balling it I believe the angle is there to play a good object ball, however, lets not be mistaken, it's all about the cue ball. Playing a good cue ball will allow you to be more efficient with shots of this kind, all that's left is learning to judge the angle of the object ball in relation to the path the cue ball will take. Yes, this takes practice which is necessary to develop the feel for shots of this kind.
Frank, my explanation of the above was not meant for you, I know you are very much aware of how shots like this one are played out, but for players that are not familiar with this type of hit then my explanation will hopefully be of some benefit.
Dr. Bill