Our plans always assume that you are starting at the main gate to a park. Since the parks generally let folks past the entrance and into parts of the park before the official opening time, we hope our customers have arrived early enough to be well past the main entrance. In most cases you are not actually allowed on the rides until the official park opening, but you'll have a shorter walk to your first ride than if you were at the entrance.
In addition, wait times for top rides vary significantly first thing in the morning, depending on your location within the horde of people heading to them. For example, someone who arrives early and walks aggressively might be at the front of the pack and have a near-zero wait on Seven Dwarfs Mine Train at the start of the Early Theme Park Entry period. Someone who arrives a bit later could wind end up near the end of the pack and have a 45-minute (or longer) wait, even though both are people are there for "rope drop."
Since most people can't be at the front of the pack, our software uses conservative (long) estimates for just after park opening. That means that even if you select Rise of the Resistance as your first attraction, our software will predict a long wait for it.
We are looking into better solutions for people that will be at the park very early, and we may be able to offer something better in the future, but in the meantime, if you are totally sure that you will be at the park early and toward the front of the initial crowd you can remove your first ride from the plans. That way you can ride exactly at park opening and continue on with your plan (or a re-optimized version of your plan) afterwards.