Not Buchanan. This was someone at a major studio making high quality films at cutrate prices. Actually his films bore no relation to what we now call the B movie. There's all sorts of arguing about what it should mean, but before there was the name B movie there were 'Poverty Row Pictures.' These were companies that were outside the system yet still a small yet full fledged studio making really, or should I say REELY, small budget fan service films. They might make as many as a major and more than a minimajor, but the budgets might be less than 10%. The term B movie wasn't in use.
Prior to 'Stagecoach,' Republic Pictures kept John Wayne busy, as they did Gene Autry and Roy Rogers. They claimed to make a film in a month - Project chosen on the first Monday and off the write the script which is approved on Friday. The second Monday begins preproduction, the third Monday starts a week of shooting. They're already editing at the end of that week, but the fourth Monday they have to kick it into high gear, because the following Friday they're supposed to be done.
Just another example of the destructiveness of government intervention and breaking up "Monopolies," it was the forcing the studios to give up ownership of theaters that put all but Republic out of business, as the theaters that couldn't get major studio product were then competing for that and didn't need the Poverty Row studios anymore.
Oh, the closest thing to Poverty Row I can think of now is the Asylum. They started out making these 'Goth Softcore' movies, but they moved on to low budget knockoffs of the upcoming major releases. Literally in the theater at the same time as 'Transformers,' 'Battleship,' 'The Day the World Ended,', etc. was 'Transmorphers,' 'American Warships,' 'The Day the World Stopped. . . .'
Oh the subject of a B movie being produced as part of a double feature, those were often shorts, perhaps 3 reelers, but still professionally at the level of the main film.
Anytime you ever see these writeups about B movies they're always using it in the context so many do today. But that's not the original meaning of the term.
So getting to that 'Look' of the film that seems the frame rate is wrong or something. Things that contribute to a film not looking "Right":
If you use a cheap or badly maintained movie camera, the "Registration" of the film pressed exactly in place at the moment of exposure can give it a wrong look.
Nothing unusual about a cheapie film being improperly lit and exposed, the wrong shutter angle set in the camera, etc. By the time it's released it can really look funny.
A cheap film might not get the correct 3 light timing in the lab.
All sorts of better staging might occur when there's a budget, you might just be seeing actors rushing in a way they wouldn't in a film with higher expectations. The actors look like they're moving quicker when they're closer to the camera, larger in the frame, etc.
They sometimes do 'Undercrank' during filming, speeding up movement. There was a time when there wasn't uniform shutter speeds and films might not run at the right speed. A lot of old silents are transferred to film at 24 frames per second with they were shot at 16-18. Imagine some of Charlie Chaplin and Buster Keeton trademark moves if you watched them slower. Or they might have shot them intending to look that way from the beginning.
Ah, but how could I know for sure what you really mean? I want to say you're seeing something that is a symptom of the lack of money, but it's hard to be sure.