if anyone getting anything less than 10 with 1800 premio of 2005-2007 (old) better check your car and if you're using anything heavier than 10w-40 oil change the stupid mechanic who told you this, believe me one day he'll destroy your car.
now for avg, according to toyota premio 2005 - 2007 (old)
worst avg 1.5
better avg 1.8 (this is not cvt)
best avg 2.0 (cvt)
my avg 11 to 12 with ac anyday in city and 15+ on highway at 120 or less.
@140 to 160 speed you'll get 12 max.