While Command Sergeant Major is a proper title, Command Sergeant could be an informal title in a small Army unit. We have a similar case in my Navy with “Leading Petty (enlisted sailor) Officer” where the unit does not have a Chief.
Just a guess.
I suppose you could be right.Although I never ran across this during my stellar (cough,cough,choke) Army career that doesn’t mean it’s not used..informally at least.
If (and we often do) cut a word off the rank, it’s “Command”, leaving “Sergeant Major”.
Other senior enlisted— I never heard a Staff Sergeant (E-6) do it— might call him “Smadge” to his face, while lower NCOs might refer to the “Smadge” among themselves.