You can't sync them, both most have the same driver. I've tried, eventually I had to upgrade one of the driver to QD. But, the wireless card on both is the same.
They probably meant, if you upgrade to QD. wES/wQD won't sync but they will sync for feed mode. Either way, I didn't find a real benefit to syncing a mp10 to mp40, as I run my mp10 at 100% and mp40 at 40%. Syncing them resulted in too much flow or not enough.
I've got a MP40wQD and a MP40wES synced up together with no problems. Even before I got my WXM. Now they are even anti- synced together running through my Apex.