Since they always advertised their buses as arriving approximately every 20 minutes, it’s probably specifically designed to show that interval. They probably didn’t think the average guest would notice or care.
Where I have an issue is the arrival times for pick up. It’s like the checkout lines at the supermarket. No matter which one you pick, that’s the one with the worst service, lol! While I like that they try to give us timing info for the buses, my personal experience is no matter where I am going, I can count on that time being pushed back a good ten to fifteen minutes every time, and seeing three of every other bus before mine pulls in. It is what it is. Of course the destination arrival time would get pushed out accordingly.
I do try to avoid the last stop if I can around opening time, at any resort with multiple stops, even though technically I suppose most people would think that is the one with the best timing for a direct trip. I can’t tell you how many times I waited more than an hour for buses at the last stop at POR because they would get full and head to the park, and no one bothered to see if anyone was waiting at the last stop. A couple days of that, and I learned to walk to one of the other stops instead.