Asset Bundles compatibility for mobile

Is it still true that asset bundles are not compatible between iOS and Android? What is one way to create an asset bundle once and use it on both iOS and Android?

http://unity3d.com/support/documentation/ScriptReference/BuildPipeline.BuildAssetBundle.html?from=AssetBundle

As far as I know, you’ll have to build the asset bundle once per platform you intend to use it with.