I dont know if this is a Galaxy S2 or ICS Bug or not ?
When using "PhoneSms" to send SMS from B4A Application
it sends always 2 SMS's.
I know there are other SMS applications like Handcent and others,
doing exactly the same thing with Samsung Galaxy S2 with Stock ICS 4.0.3.
PhoneSms uses the native SmsManager to send a single message. There is nothing much that can be changed in this implementation.
This is most likely a bug in the ROM you are using.