cwerdna Thanks for the link. Sorry that you had to go to the trouble of finding what I should have found myself. I found the owner's manual, but somehow missed the separate document covering the warranty. Probably at the time I didn't think they would split it into two separate documents and stopped looking after I found the owner's manual.
rosier9 My "guess-o-meter" is about 30% off at full charge, dives quickly to part way correct at about 70% charge and then slowly converges with reality as you approach zero charge. No, I did not use that in my calculations, and I was very disappointed that the Nissan dealership did use that to say my battery was fine.
I did all my calculations based on trip odometer miles divided by 1 minus the remaining charge as a fraction, and ran down to 30-35% to minimize the extrapolation. I have only analyzed 3 trips that went down that far and got extrapolated total ranges of 52.46, 55.45, and 62.17 miles (100% to 0%). The guess-o-meter predicted 82 and 77 at 100% charge for the same trips. I don't know why the first run got the anomalous 62 miles. Maybe after driving and analyzing a few more runs the data will either show a spread of ranges between 52 and 62, or that most cluster in the mid 50s and the 62 really is anomalous.