If you're using the odometer as a fuel gauge, surely volume becomes irrelevant for judging your range (excluding the tuning purposes)? e.g. My tank lasts 200 mi

If you're using the odometer as a fuel gauge, surely volume becomes irrelevant for judging your range (excluding the tuning purposes)? e.g. My tank lasts 200 miles => I've gone 100 miles => I can go another 100 (top) before refilling.