Right, my curve example was just to show what the control points look like in RB. If you load up a file with no custom curve edits, there will be no control points in RB listed. I'm pretty happy with the results of Audyssey without having to add a lot of edits, so in my case, just lowering a broad range did the trick for me.
Since the app and RB cannot be used exactly like a PEQ, you will need to use probably 3 control points per adjustment for narrow adjustments. Ie. there is no "Q" to let you tell it how wide you want the change to be, so use 1 control point below and one above the frequency you're trying to change with the middle control point being the actual adjustment.
Something like:
#1 200Hz 0dB
#2 300Hz +3dB
#3 400Hz 0dB
You may also have to "fight" against Audyssey's pre-programmed overarching curve depending on the type of adjustment you're trying to make (ie. the rolloff up high and down low. To check how things are looking, save your edits and transfer back to MultEQ app and look in the "room correction results" section. Scroll through all speakers/channels to let it compute the new predicted curve. If something doesn't look right, go back to RB and try again.