anniversary discrepencies

I had a vehicle insured with discovery which commenced on 1 November 2017 which anniversary increase on the policy was 1 November 2018 which was perfectly fine. I subsequently added another vehicle for cover which commenced 30 January 2019 and have cancelled the previous vehicle cover. So I get the annual increase notice and see that the renewal for the vehicle added 30 January 2019 has an early anniversary date which is 1 November 2019, how is this correct? How can "12 months lapse" on a vehicle added in January 2019? What is more frustrating is that I call your call center to get the discrepancy resolved unfortunately an agent can only help so far, there is a query logged on ***