The easiest way to figure out if you are within the three day window is to go into the Deviate Trips page in VIPS. Enter the date you want to buy the ticket on the day you’d be deviating from. You don’t have to have a scheduled deadhead. You should have a Select option for the first and last leg of the trip. Enter when and where you want to fly and select one of the options that comes up. You don’t have to actually deviate. Just click on the flight. If it’s outside the three day window for the leg you are deviating from it will tell you. It will say “The ticket departure time is not within the three day deviation window”. If it doesn’t say that, you’re good to go.