Uh... yeah.
Imagine, inside a turret: cramped, single loader, no handlers = 1 or 2 shots depending on training.
Now imagine, behind gun: lots of space, probably 2 loaders, 2-4 handlers = 1 shot regardless of training.
Wilhelm von Thoma with the ground element of the Condor Legion in the Spanish Civil War, and a tactical observer for for the Wehrmacht, noted that it only took a "few" anti-tank to breakup a substantial armored attack.
When the Germans launched there spoiler attack at Mareth, a British staff officer noted that the AT guns fired off 17,000 rounds in 20 minutes. (For some reason it was a short attack.)
Right, AT guns get one shot.
