I think the tiller and NWS will sum - unless you have pressed the disconnect button on the NWS which will disconnect the rudder input so that you can do the Flt Ctl rudder check on the move.
It used to be that, on an auto land, if you did not disconnect the AP before you started to vacate the RW, you could override ROLLOUT and steer off the RW using NWS. Unfortunately, when you released the tiller, ROLLOUT would attempt to regain the CL using the NWS.
At some stage, Airbus redesigned the software so that, when 25 degrees off the RW CL, the AP would disconnect automatically. Happiness!!!
mcdhu