On upstream thats true ignition so yeah upstream shaping 'should' be more effective than downstream shaping on QoS. Of course only time will tell.
Interesting how you labeled the downstrean shaping as cost control.
What I would like to see is on this shaping it be on 24/7 (why should good quality service only be during peak?) but it also be dynamic based on utilisation so its only shaping what it needs to shape not for the sake of it. I expect tho VM will do the easy way which is just a basic sledgehammer as you say and only during peak.