Hosing "Best Region" issue

I am developing an app for Android phones.

I notice that if I set Hosting to "Best Region" and Enabled Regions to "Everything", then the app running on my development PC does not see the same set of rooms as the app running on the phones. When this C# code is called on the PC, it prints out the message "zero rooms seen from lobby"

RoomInfo[] rooms = PhotonNetwork.GetRoomList();
bool inLobby = PhotonNetwork.insideLobby;
if ((rooms.Length == 0) && inLobby)
{
Debug.LogWarning("zero rooms seen from lobby");
}

The apps running on the phones can see rooms (each other's rooms). And if I build the app with Hosting set to "Photon Cloud" and Region set to "US" then the PC is able to see the same rooms as the phone apps, and the above message is not printed.

I would not have expected this behavior because both my PC and my development phones are in the same place and connected to the same WiFi network. Is this the expected result, or am I doing something incorrect?

Thanks

- David