Trouble with loud speaker off on Galaxy S

Has anyone else experienced this on the Samsung Galaxy S?

When I use the folowing to turn the Loudspeaker on it works fine:

audioManager.setSpeakerphoneOn(true);

But when I try the opposite to turn it off:

audioManager.setSpeakerphoneOn(false);

The Loudspeaker stays on and audio is played via that instead of the ear piece on the device.

The above works on the Nexus One and HTC Hero, just got a Samsung Galaxy the other day and it doesn't work, has anyone else encountered the issue and perhaps know why it is happening and if there is a work around?

Here's what I have to do to get it to work:

if (isGalaxyS()) {
    audioManager.setMode(AudioManager.MODE_IN_CALL);
    audioManager.setMode(AudioManager.MODE_NORMAL);
    audioManager.setSpeakerphoneOn(flag);
}

Seems that this back and forth somehow resets the audio channel. For completeness here's isGalaxyS() (note that I've only tested this on the Epic!):

public static boolean isGalaxyS() {
    String model = Build.MODEL;
    return  model.equalsIgnoreCase("GT-I9000") ||       // base model
            model.equalsIgnoreCase("SPH-D700") ||       // Epic         (Sprint)
            model.equalsIgnoreCase("SGH-I897") ||       // Captivate    (AT&T)
            model.equalsIgnoreCase("SGH-T959") ||       // Vibrant      (T-Mobile)
            model.equalsIgnoreCase("SCH-I500") ||       // Fascinate    (Verizon)
            model.equalsIgnoreCase("SCH-I400");         // Continuum    (T-Mobile) 
}