The Adjusters

I checked further: The Adjusters series seems to be one of those men's adventure series that filled the paperback racks in the late sixties and early seventies. It was first written by Peter Winston (about whom I know nothing, and Abebooks seems no other books by him). The final entry in the series was written by Jack Laflin. The cover of the last book says: "The Adjusters: an organization unique in the annals of counter-espionage". It also seems that Peter Winston was the hero in the books - so why was Laflin's name used in the last novel (and why the two-year hiatus between the fourth and the five books?)?

Here's the list, from Abebooks:

Assignment to Bahrein, Award 1967
The ABC Affair, Award 1967
Doomsday Vendetta, Award 1968 ("Dispatched to solve a murder in Tangier, A-2 is trapped in an espionage network bent on destroying America's most strategic missile bases.")
The Glass Cipher, Award 1968 ("Agent A-2 on a brutal spy hunt that begins with the biggest sellout in international espionage.")
The Temple at Ilumquh, Award 1970 (written by Jack Laflin)