This is the tutorial on the subject. Devices - Allow or Prevent to Wake Up Computer
I think the keyboard has to be turned on to wake from sleep if you turn the mouse off.
I'm not 100% and you made no mention if keyboard is enabled to wake.
You need one or the other. Mine for some reason defaulted on install "mouse off" and "keyboard on".
When I hooked up the Logitech K320 keyboard the keyboard stayed on and the original wired mouse off.
Something to check. Follow the tutorial it might make it easier.
If you already know the keyboard is enabled then disregard.
By the way it is much nicer waking using the keyboard.
Hope this helps.