Let's see if I can bring something new to this discussion.
You all seem to take for granted that you initiates or are able to catch ukes ki in the upward motion. Now and then we use to train the actually shomen uchi as the strike and then it's no good to crash into the arm trying to go towards the head. No that is the time when ura blending is in place. Step of the line with both your arms raised and smoothly follow the strike down to the floor allmost as in nanakyu.
Well that's true. That is only an save face technique. I mean, obviosly you are so good that you caught the evil mans strike allready in the upward motion and proceeded with a fancy ikkyu... but if not!