It doesn't look like this is a fair comparison. If you ported your app from IOS to Android, then presumably the IOS version has had the opportunity to gain popularity already, which the Android version has not. I'm not a mobile app dev, but I assume that it takes some time before an app can gain popularity and hit it's sales peak.

It may make more sense to compare the first two weeks of IOS sales to the first two weeks of Android sales, even though they'll be different dates. Or, maybe that is what you're comparing and I just missed something.