The Check Digit is "easily " to calculate .This is how you do it ...
First the letters of the prefix ; they have the following value :
A B C D E F G H I J K L M
10 12 13 14 15 16 17 18 19 20 21 23 24
N O P Q R S T U V W X Y Z
25 26 27 28 29 30 31 32 34 35 36 37 38
 
Lets take a random container : MWCU 605 978
The prefix MWCU has the value :   The value of the numbers are equal to the containernumber :
Letter : M W C U Number : 6 0 5 9 7 8
Value : 24 35 13 32 Value : 6 0 5 9 7 8
 
Now make the following calculation :   Now divide 7858 by 11 by long division .
The remainder is the Check Digit .
( if the remainder is 10 , the check digit is 0 ).

11 / 7858 | 714
       77
       -------
          15
          11
       -------
             48
             44
        --------

               4

 

M 24 x 1 = 24
W 35 x 2 = 70
C 13 x 4 = 52
U 32 x 8 = 256
6 6 x 16 = 96
0 0 x 32 = 0
5 5 x 64 = 320
9 9 x 128 = 1152
7 7 x 256 = 1792
8 8 x 512 = 4096
Total : 7858
The complete Containernumber is : MWCU 605 978 - 4