I have now. I have to say that on many legs of my trip I ended up above the line even when I was going 75 or 80 MPH. Sometimes the original Trip prediction was telling me that I would have a really low charge left at the end (b/w 3 and 5%), but it would often go up over the course of that leg. I think that some of the reason might have been that I was starting off with a cold battery. Or course, if I was travelling through slow traffic or construction, then my range would also go up.
Maybe the energy calculator gets better over time - and since I was on a long trip, it could better estimate what my usage might in fact be.
There was a leg where I was driving north in Northern California. I can't remember the exact numbers, but it went something like this: I had about 180 miles of range in the 'tank' and I had about 130 miles to the next SC. The Trip calculator suddenly was telling me that I was going to arrive with about 2% battery. At the time it didn't make sense to me. But slowly as I progressed through the trip I could see that the Range was dropping faster than the miles were clicking off. I modified my speed slightly - going at the speed limit or sometimes 5 MPH less when we were in 70 MPH speed zones - and the Trip % started climbing up above 5 %.
In hind sight, the answer was simple. The SC stop that I was travelling to was Mt. Shasta - and my trip was a gradual 2000 meter climb over those 130 miles.
There was another time going through Colorado where the Trip prediction graph actually went up as you scanned rightward on the graph line. This was where we came over a pass that then descended into the Dillon SC. At the top of the pass I had 40 Miles of Range left. At the bottom of the pass I had 48 Miles of range - and this was when I was driving 70 to 80 MPH.
I'm not sure if this really answers your question directly. But during the trip I never had an issue where the trip calculator predicted that I would be OK and reality showed that I would be cutting it close. By the last week of the trip, when charging I would enter the next SC stop in the Nav, turn OFF 'Route Me Through SCs', and then display the Trip app. When it got above 3% predicted battery at destination, then I felt good to go. Without modifying my driving style, I always ended up at the next SC with more than predicted (unless I really got heavy on the accelerator in the last half of the leg).