Just because it does 22.5 in 10.15 cycle you can't say it does well on fuel. Besides what's in Japanese next to the 1.0 L says it does well in city traffic, not in long distance runs ( Yeah, I do read Japanese ). That contradicts what you have said earlier.
and below the page following text can be found.
燃料消費率は定められた試験条件での値です。お客様の使用環境(気象、渋滞等)や運転方法(急発進、エアコン使用等)に応じて燃料消費率は異なります。
which means above figures are in testing conditions and actual figure may differ due to temperature, traffic, driving style, (sudden acceleration, use of AC) etc.