I can reply here since it might be of interest for other users.
Which product are you using?
Please note that, in general, the Datecode can be decoded as follows: 711D4
"7" means 2017
"11" means wk 11 2017
"D4" is the product code
So basically your product has been assembled (and the marking printed) in wk11, but the lot name is given by the test week, that could be wk12 in your case, so your guess should be effective.