Exploring the world one toilet at a time.
That math doesn't add up. There is a relationship between hp and fuel consumption and in this case (naturally aspirated) you're increasing about 12% in hp but claiming fuel consumption is up 50%.The 160HP burns 7.9 per hour. The 180 burns 12/hr. If your plane flies 80 hours a month thats roughly $20k per year in savings.
By the way, the only time I've seen 12gph out of a 360ci Lycoming was in an aerobatic application.