QoS not applying question

I am just configuring QoS in its basic form. I have two interfaces on a Cisco CAT3750x switch and two PC's running iperf to test throughput.

Interface configs are as follows:

interface GigabitEthernet1/0/9 description PC-1 switchport access vlan 999 switchport mode access spanning-tree portfast edge ! interface GigabitEthernet1/0/10 description PC-2 switchport access vlan 999 switchport mode access srr-queue bandwidth share 1 70 25 5 srr-queue bandwidth shape 30 0 0 0 priority-queue out mls qos trust dscp spanning-tree portfast edge ! 

At the moment PC-1 is acting as the server and PC-2 is the client pushing the data. As it stands now, when I push data via iperf marked as DSCP value 46, it gets shaped to about 37mbps and then the other "data" stream caps out at about 902mbps (which is what I expected). Keeping the configuration the same, if I swap the roles of the PC's and make PC-2 the server and PC-1 the client they both the data and voice streams get about 477mbps each. I assumed this was because I didn't have a QoS config on port 9. However, the commands on port 8 should apply QoS on traffic coming out of it so it should be doing 30/902 like before?

At that point in my mind, I think "maybe I need to configure the same QoS settings on port 9". So I do:

interface GigabitEthernet1/0/9 description PC-1 switchport access vlan 999 switchport mode access srr-queue bandwidth share 1 70 25 5 srr-queue bandwidth shape 30 0 0 0 priority-queue out mls qos trust dscp spanning-tree portfast edge ! interface GigabitEthernet1/0/10 description PC-2 switchport access vlan 999 switchport mode access srr-queue bandwidth share 1 70 25 5 srr-queue bandwidth shape 30 0 0 0 priority-queue out mls qos trust dscp spanning-tree portfast edge ! 

Now, no matter which PC is the server and which one is the client. Both the data and voice streams are getting about 477mbps each. Despite there being QoS settings on both interfaces. If I take the QoS settings back off port 9 and do the initial test again where PC-1 is acting as the server and PC-2 is the client. It goes back to 30mbps voice and 902mbps data.

Am I misunderstanding something here? I have a feeling it may be related to the difference between input and output queues?

The only other QoS command on the switch is the 'mls qos' command to enable QoS globally.

Im new to QoS so have probably misunderstood something!