An opposed stat isn’t really two different stats, it’s one stat with another word at the far end of the stat bar, to highlight what the reverse of the main stat name would be. There’s more information on opposed stats on this page of the wiki.
If you put ${logical} in your text, you’d see the change (logical would now be 55). But you’re not changing {impulsive}, here, just {logical}—which you have set as both the extra word in your {impulsive} stat bar, and as its own individual stat.
In order to get impulsive to go down and logical to go up, you’d want
*fake_choice
#What?!
*set impulsive -5
Also, I think stats may be case sensitive? I would suggest using lower case for variables, just to avoid any potential problems.
And finally, your indentation needs to be even. If you use four spaces to indent, every level of indentation needs to be four spaces—so the first indentation here, for your option, would be four spaces, and then the indentation for *set would be eight.