If there are lines with contract starting in Sep 2013, meaning that they are still under contract, then those particular lines wouldn't be receiving the discount on the new plans (since they are under contract still), right?
As far as I'm understanding all this, yes, I believe that's right. I have a contract that started in September 2013, but I have the discount because we just recently switched to a 15 GB Mobile Share Value Plan.
Also, from what I understand, if you have this discount currently, and decide to upgrade to another phone on a 2-year contract, then you will stop receiving the discount.