Fulminato
Mostly because I didn't find a way to include the consequences of that optional scene without the table becoming unreadable. So I've put forward a physicist hypothesis that the player wouldn't meet the conditions for the scene in an otherwise optimized route.
In other words, I lied to make my life simpler.
But yes, with a combination like Sabitha Airship + Esthera Fleet + Mestan Island, there's an extra IW_VP +1, Sabitha +1 on the left.