Many people, including myself, sign on with Koodo because we can do so cheaply and without a contract. However, every time a tab on a phone is paid off, or a phone breaks and needs to be replaced these customers assess their other options. If Koodo could have a continued customer sale of or policy for contracts whereby someone who's tab was paid off was then able to apply a % discount to a contract - more customers might sign on for a longer period of time.
For example, Customer 1 signs on with koodo and buys a mid range phone on a monthly contract with a tab - rather than a 2year or long term contract. That phone either breaks or the tab is paid off and the customer recieves an email offering a 25% "loyalty" discount on a 2 year contract should they wish to sign up for one of those.