This is interesting. Having just learned that the story "Frog Men Against Belzar" had originally been intended for publication in Ziff-Davis' SPACE BUSTERS comic before it was cancelled with issue #2, I went back to have another look at SPACE BUSTERS. In the St. John DARING ADVENTURES issue, the names of the Space Busters characters Captain Brett Crockett and Sergeant Bolo have been re-lettered as "Captain Andall" and "Sgt. Bala", but more interesting than that is the fact that the original Ziff-Davis SPACE BUSTERS comic book bears the notice "Copyright 1952 by Approved Comics Inc." on its first page. Since "Approved Comics" was more or less the official name that Archer St. John chose to operate under as a publisher, and he became heir to some of Ziff-Davis' unused inventory stories, this leads me to suspect some sort of previously-undocumented publishing arrangement between Ziff-Davis and Archer St. John.
Link to the book:
Approved Comics 06 - Daring Adventures (alt)