I've always wondered where on Earth Bendis got the idea of having these Avengers voices in Marc's head, when every Moon Knight book I have ever read has just had Khonshu. His own explanation was that Marc had done the same with Grant and Lockley, but once again, I had never seen them portrayed as anything other than cover guises...
... and then I read West Coast Avengers.
In this series, Moon Knight appears in 20 of its 46 issues, and within its pages, he has the voices of Grant and Lockely telling him what to do, just like the Avengers now do.
So based on this new evidence, it's fair to conclude that Bendis read West Coast Avengers back in the 80's... and hasn't read any Moon Knight since :P