I've seen some discrepancies too although maybe not quite as drastic as 20-25%.I knew it wasn't just me experiencing this. My theory is that the app probably uses some generic algorithm based on ideal conditions, while the car's estimate is more dynamic, factoring in your actual driving style, terrain, and even climate control usage. I think of it like the difference between a theoretical "brochure" MPG and what you get in real life. I wouldn't rely solely on the app for trip planning. Always double-check with the car's own range estimate, and even then, be conservative, especially if you're pushing it. As for a fix, I'm not sure there is one, unfortunately. It's probably down to Nissan improving their algorithms and data syncing between the app and the car.