The cutoff, lead-time, and blackout-date rules you configure live inside your date picker app and control what customers can select at checkout — EasyRoutes doesn't import those rules. What it does read is the resulting delivery date and time window the app writes onto each order, which it then uses for filtering and routing. So the customer-facing scheduling limits stay with your picker, while EasyRoutes plans around the dates and windows they produce. This applies to both EasyRoutes for Shopify and EasyRoutes for Web.
See: How EasyRoutes works with your Shopify setup and third-party apps · Time Windows