Devices

I have been using Norton 360 for 3 years.  Set up on automatic renewal and pay $86.00 per year.  I have license for 3 devices on which the Norton 360 has been installed..  I have seen an offer to purchase the Premium program for a discounted rate of $59.00 with license to install on 10 pc's. Why has Norton not offered the additional pc's to subscribers?  It appears that I should not renew the existing subscription and purchase the new offer.  Save money plus get additional devices for which to install Norton 360. Anyone also ran into this situation?