How Does Lengthening the Settlement Window Mitigate the Risk of an Attack?

Lengthening the settlement window mitigates the risk of a settlement window attack by increasing the time and capital required for an attacker to sustain a price manipulation effort. Since the final settlement price is an average over the entire window, a longer period makes a temporary price spike less impactful on the final calculation, forcing the attacker to spend more to manipulate the price for a sustained duration.