Battery capacity is measured in kWh, not "KW". See viewtopic.php?p=520169#p520169
In all previous Leafs and I suspect it to be true w/the '18 40 kWh Leaf, as well, not all the battery capacity is user accessible. Some is intentionally left unusable (not user accessible) at the top and bottom of the battery.
Back to the range chart, on a 30 kWh Leaf w/new battery, it estimates that if you went 45 mph steady speed at 70 F, no HVAC usage, etc. (see conditions), you should average 5.5 miles miles/kWh (or if that's what you averaged) and should be able to make it 154 miles until dead. If you went 75 mph (or averaged 3.3 miles/kWh), that car should be able to make it 92 miles.
Further down, there was a chart for 24 kWh battery (e.g. Use this 100% chart for a factory new battery), 35 mph estimate is 6.3 miles/kWh or 132 miles until dead vs. 75 mph (3.0 miles/kWh) of 62 miles until dead.
Edmunds achieved exactly 132.0 miles until dead on a 2011 Leaf doing 35 mph: https://www.edmunds.com/nissan/leaf/201 ... r-end.html
. That car has an EPA range rating of 73 miles vs. the 2018's 151 miles.
TonyWilliams asserts the speed at which max range is achieved is 12 mph.