The way you have configured shaping rate is equivalent to "transmit-rate x exact". You can use either one of them, but not both to confuse the system.
However, a more common way to use shaping-rate is on a Traffic Control Profile (TCP) which is applied on a physical interface or logical interface. Let's say you have a 1G interface applied with a TCP with 20% shaper. The total BW for the interface all queues are 1G * 20% = 200m. Then you apply a scheduler for a specific queue, let's say 80% for BE. Then your BE queue has 200m * 80% = 160 m dedicated BW. You can use "exact" option on the transmit-rate so that another layer of shaping is performed