@MasterLillyclaw I’m sorry. I’m not following your question. Lots of people do better on one test than the other. What I’ve advised students to do is to take each one (with prep!) and see which you do better on. Then take that one again at least one more time with more prep work, unless you are already satisfied with your score. Because many students do this, there is often somewhat of a difference between the ACT and SAT scores. Since Stanford requires you to send in all scores, they would see this frequently.
As I recall from my d’s application, for the ACT portion, you could just send in the highest score and self report the others if it was a financial hardship, since the ACT charges for each individual test score sent to each school. You should not use score choice with the SAT. All scores need to be sent to Stanford and it is the same fee no matter how many scores you send to a specific school.