If a contract states something like “Within 154 days after proceed date in LNTP” - in this case would use the day after NTP as Day 1. How ofter do you count NTP as day 1 vs the day after. I know using NTP as day is less hassle, if using the next day you actually need two milestones to get the roll-up count to work better, but still a hassle. People think they are doing the contractor a favor by making the next day - day 1, but it is more of hassle on the schedule.