Thanks!
So if I wanted both X and Y scale to be affected differently by the vertical motion of another layer I could use
x = position[1];
y = position[1];
x_temp = thisComp.layer(“UPDOWN”).transform.position[1];
y_temp = thisComp.layer(“UPDOWN”).transform.position[1];
x_result = linear(x_temp, 150, 280, 65, 100);
y_result = linear(y_temp, 150, 280, 75, 100);
[x_result, y_result] ;
?