I think I pulled out too little of the quote and it lost it's context. You had noted:
...I believe with this you are claiming A2-73 has allosteric binding at the S1R. If it does it certainly would be significant but I don't think there is evidence for that. I'm not sure of which Maurice paper we had discussed but if you have the reference handy that would be helpful. I can probably find it but likely not going to have any time today.
I also don't think anyone has ever made a case of a defined distinct MOA for 2-73. The closest is pointing to it's additional muscarinic activity. Of course DZP has muscarinic activity as well...though via a slightly different mechanism. I don't see those distinctions as significant though some may. The key imo is distinct S1R activity and ability to bind in the presence of higher affinity compounds, esp. DZP.