The $180 ($15 x 12) is assigned automatically by the system as a plan feature, no different than the fact the $35 plan comes with 5GB data. Asking an agent to confirm is an invitation for story telling. It's not up to them. Referrals are a totally different credit subject to their own terms. That separate limit is $300 per line and up to 7 lines if you have many lines in an account. My Koodo account has referral credits, bill credits from activation, SPC credits from phone purchases. None of each credit stream affect each other.
Public Mobile 2016 fall promo, $23/1GB, $38/5GB, $28 RBC 5GB promo