We have no idea how it would even be possible to make these horizontal adjustments with the typing machines of the time.
I agree with the other comment here that the authors haven't used a typewriter, or at least in enough detail to know that on many if not all of them, holding down the spacebar will advance the carriage by half a character (and releasing it, in normal use, advances the other half.)
I agree with the other comment here that the authors haven't used a typewriter, or at least in enough detail to know that on many if not all of them, holding down the spacebar will advance the carriage by half a character (and releasing it, in normal use, advances the other half.)