Static compression ratios matters most when the throttle is wide open, getting maximum air intake charge and the engine can actually achieve something close to that number in dynamic compression. So yes I believe in a towing application where there is heavy load, a higher octane could significantly help performance and MPG. In everyday driving and moderate throttle input, where the dynamic compression rarely approaches static compression numbers, you can generally run lower octane with little impact although GDI engines are proving troublesome with this approach. A good example is how fuel stations at high elevation can sell lower octane (85) than sea level locations (87) because the cylinders just aren't getting a full charge. Just my $0.02