While Android is practically running neck and neck with iOS in terms of raw distribution, developers are still flocking to Apple’s platform because it monetizes three times as well, according to Flurry.

The mobile analytics and monetization company took a look at project starts going into the holiday quarter across its network of 135,000 applications. It found that for every app being started on Android, there are three being worked on for iOS.

It’s especially striking considering that Android is edging in on Apple’s numbers around cumulative device sales and downloads per month. The latest official statistics from both Google and Apple have Android at 200,000 cumulative device activations and iOS at 250,000 devices sold. Comscore has also been reporting that Android has surpassed iOS in terms of mobile subscribers in the U.S. for months, but their data excludes the iPod, iPad and international markets.

What is even more surprising is that Flurry is reporting that Android’s market share in terms of new app projects on its network has actually declined since the beginning of the year. Android used to make up one-third of all projects. Now it’s down to 27 percent.

Why the difference? Basically, it’s monetization.

For every dollar an iOS developer earns on Apple’s platform, the average Android developer takes in 24 cents based on in-app purchases. (Flurry’s analysis seems to exclude advertising revenue and from what I’ve heard anecdotally, Android developers are generally more reliant on advertising because paid conversion isn’t as good on the platform.)

The lower conversion rate has to do with the fact that Apple requires every consumer to set up an iTunes account with payment information when they buy their device. That strategy has helped Apple round up at least 225 million iTunes accounts with credit cards and other payment methods ready to go. Not only that, the company is rounding out payments options in China, which has quickly become Apple’s second largest market in terms of revenue.

Google only recently started forcing new Android users to sign up with its payment system Checkout. The company is actively trying to fix this problem.

All things considered, I would take a more nuanced look at Flurry’s conclusion. In general, it’s true that iOS monetizes better for developers. I generally hear a top-grossing game can do between $2 and 3 million per month on iOS. We’ve seen around a $1 million monthly runrate on Android for the top-grossing game after Google’s cut, according to figures from Russia’s Game Insight.

At the same time, I’ve come across multiple cases from developers including Spacetime Studios, Animoca and Storm8 where Android actually monetizes better on a per-user basis.

Each case is special. In Animoca’s case, the company basically does more comprehensive quality assurance testing than other rival developers. The company, which recently raised funding from IDG-Accel, has an unusual volume-oriented strategy where they release one to three apps a week. The company’s founder Yat Siu has told us that because its games actually work on a variety of Android devices, users choose them over competing, malfunctioning apps from developers that don’t QA test their work as thoroughly.

Android can also monetize better if a developer targets a more hard or midcore audience. Austin’s Spacetime Studios said its massive multiplayer titles like Pocket Legends do better on Google’s platform partially because Android has a demographic of users that are more hardcore. There’s also not as much competition for the type of game the company provides on Android.

Storm8 is another example. It was an early leader on iOS, but increasing competition has pushed its games progressively lower on the iOS top-grossing charts. Storm8′s Zoo Story 2 now has to compete with Zynga’s very polished Dream Zoo. Its original RPGs like iMobsters and World War have to face off with Funzio’s Modern War and Crime City.

Android doesn’t have anywhere near the same level of competition although I expect this to change in the next 6 to 12 months. For now, Storm8 seems to be taking advantage of green fields on Google’s platform. Other developers who take proven concepts from iOS and are as diligent with data and optimization as Storm8 is can probably do the same.