The working incrementing code:
void loop() {
for (int data=0b0000000000000000; data < 3891; data++){ //Increment upto data<xxxx
commandPlusData = command | data;
digitalWrite (ssPin, LOW); // pin 10 - initiate serial communication
SPI.transfer (highByte (commandPlusData));
SPI.transfer (lowByte (commandPlusData));
digitalWrite (ssPin, HIGH);
}
}