Hi Maria,
Thank you for your comment.
We have already tried to set this parameter so the SPQ appeared always after supplier's login. Afterwards we had to deactivate this functionality since a lot of suppliers complained they saw the SPQ even if they had filled in all mandatory questions before (as you described in the point 1). This problem we were solving before the Ariba release 12s1.
Ideally we would like suppliers to see the SPQ only if the SPQ is not completed (missing answers for some mandatory questions) but I would say that Ariba does not support this behavior.
Thank you,
Rostislav.