You config you AI as 0-20mA,
"My Analog Input Module is configured for (0-10V) / (0-20mA)"
while you were using 4mA as min value of the range,
"For Inputs: I have been told that a 4mA signal will produce a value of 6242 (I figure it is exactly 6241.6). And a 20mA signal will produce a value...