ZS180 = 250 miles to a tank, I guess that is if you are reasonably heavy footed
I averaged 320 to a tank and that was mixed driving on a weekly commute. If I drove sensibly and kept it under 65 mph
and below 3k then it would increase beyond 350.
Don't forget, a car weighing approximately the same with an under powered engine fitted will consume more fuel when pushed compared with the same car fitted with a bigger capacity engine with more power. You do not need to use all the power all of the time in this instance but it is there when needed