I think you nailed it from a technical standpoint. On the mindset change I would emphasize that it's OK that your Planned Completion Date changes. In fact, it's ideal. This doesn't mean your implementation date has changed (yet). The project plan should reflect your estimated timeline at this particular point in time. And each time you update it (I recommend weekly), the idea is to know as early as possible when things are sliding ( and by how much ). Then it's easier to adjust. If that planned completion date doesn't move, you don't know how far off you are. If you update it every week, then every week then know where you're headed and you know where you are. And you adjust or hold the course accordingly. Now, when I say update it weekly, I'm referring to your current and upcoming tasks (not re-do the entire plan – some people have misunderstood that). But the important part is you WANT that Planned Completion Date to move to show you where you're at. It's not to say you're changing your advertised completion date. It's just showing where you are now. Then you can decide if that advertised completion date needs to change. So we always have two dates (at least) – Implementation Date and Current Project Plan Implementation Date. The former is your advertised and committed date. The latter is what your plan currently says. Then you can see if you're a day behind, no biggie. If you're a month behind, time to start adjusting to reel the date in. But if you update the plan weekly, it's more difficult to become more than a week behind in one sitting. So again, more time to react and adjust. An analogy I use, is think of it as driving across the country. You have a date you want to arrive (which doesn't change – unless it HAS to). So you google map your drive and route. As you're driving you encounter delays, road blocks, etc. Google let's you know how late you are and you can check options to adjust. Without it you don't know when you'll arrive. Your project plan is your Googlemaps. Hope that helps.
