I've just checked - if you set a 9 or 10 digit lock code then the final 1 or 2 digits are just ignored, so it should be a traditional 0-8 digit DES hash.

Can you post a screenshot of the output you get from the grep command? I'm afraid the most likely explanation is that you have mistyped it slightly.

Alternatively you could check out this thread for more discussion and another potential solution to your problem.