Just looking quickly, perhaps you could have your function return -1 if the value hasn't changed, then only print if the return value isn't -1.
You need to look over your code for other problems, too.
//Loop through and read all 16 values
//Reports back Value at channel 6 is: 346
for(int i = 0; i <= 1; i ++){
The above will only loop through two values, 0 and 1, not 16.