The average cost of acquiring a new mobile game user — formally called Cost Per Install, or CPI — is still below the average revenue companies get out of those users, according to a recent Distimo survey of the Chartboost network in Q4 2013.

In the West, it’s a narrow (sometimes very narrow) margin, with $2.52 in revenue versus $2.17 per install in the U.S., $2.73 versus $2.42 in Canada and $2.33 versus $1.86 in the U.K. In other words, games in those countries are making between 31 cents and 47 cents per user, on average, from a combination of paid downloads and/or in-app purchases, the dominant business model of mobile games.

But in the East, it’s a totally different story. Australia, South Korea and Japan do much better, with revenue between $3.82 and $6.34, and user acquisition margins between $1.84 and, in Japan’s case, $4.48 per download, on average.

The Distimo survey only covered the 250 top-grossing apps during Q4 and excluded any released before January 2012. GungHo — the maker of the Japanese mobile megahit Puzzle & Dragons, released in Feb. 2012 — is the top-grossing publisher by app revenue worldwide, according to a different report out earlier this week from App Annie, trailed by three other Japanese companies in the top 10: Line, Gree and DeNA.

Free-to-play as a business model originated in Asia and has had longer to percolate there, and it shows. China and Japan top the charts in free-to-play’s market share of their overall app stores’ revenue, at 94 percent each, versus 89 percent in South Korea and 79 percent in the U.S. last quarter.

Over the past two years, though, Japan has tallied an average of $5.32 in revenue per mobile download versus 92 cents in China, with the U.S. in the middle at $2.29. And intriguingly, even though the iPad has generated more revenue per download than the iPhone for top-grossing apps in those two years, the iPhone makes far more money in actual terms: In nine of the ten key countries Distimo focused on, the iPhone was responsible for the majority of total app revenue, with a striking 91 percent share of the iOS total in Japan.