Commander units are spawned through abilities which have their own cost rather than using whatever the squad cost works up to.
The locations of the abilities are a bit of a mess, but you should be able to find all of them by checking these folders:
All factions (usf+okw+newer soviet/ostheer commanders): abilities\faction\modal_ability\dispatch(_ability)
Soviets (original commanders): abilities\soviet\timed_ability\throw_away_hack_ui (throw_away_hack being used for 2 years now

)
Ostheer (original commanders): abilities\german\modal_ability\commander_ability\ & subfolder passive_ability