not necessarily. they will rely on others' definition of the situation the least, whereas so/sp, will rely on others' definition of the situation the most. sx doesn't check in with other people's expectations nearly as much. it does so more strategically in the process of directing and influencing and progressing towards a goal that is highly personal.
like in sex, for instance, it's not that inherent, oh, i've gotta meet the other person's expectations before i can fulfill myself. it just focuses more so on where it's going, and assumes others have a responsibility to influence and express and go after their own fulfillment. it's perspective when relating is one based on fulfillment, on deepest desire, not expectations or agreements or commitment to roles. when it's trying to be validated by others, it doesn't wait to see what validation they have to offer, it tries to win the validation it wants by conquering them, by identifying with the power, the raw attraction, flowing through the situation and wielding it.
so/sp types can be in this mode too, but it's often more formal, and more unaware of what is driving it. i know so/sp types that just want to be exactly whatever it is that others want, and i know so/sp types that unconsciously act out their desires in ways that presume a distance by attributing their own contradictions to the social games they find themselves in in order to distance from themselves, to obscure an unwillingness to really own their own conflict. this is the kind of legalese so/sp type, the one who knows how to hold down the fort and maintain their own territory in social space, but has lost a more personal connection to themselves.
other so/sp types are hyperreactive to others, and constantly wait for the other to express themselves before responding. a kind of hypervigilance to other's truth, to the detriment of their own that only comes from staying with themselves, their own experience, noticing what is arising, and owning their own feelings. otherwise there's no center, no grounding that isn't fixation, and they often feel like they are drifting away when the moods outside of them change or shift.