The quick answer: Our partners decide the Annual Growth Rate (AGR) and any other Rewards and Award offers they give to you.
The details: The partner is solely responsible for its offers and rewards. They are also solely responsible for the goods and services they provide to you and for honouring the advance payments you make to them by allowing you to buy goods and services from their participating outlets in accordance with their offer terms.
You can see the partners terms and conditions in the Offers tab on the Home screen of the app. You need to agree to these each time you make an advance payment to them. You should check them every time as they may have changed.
This creates a separate contract between you and the partner, and any partner AGR or other reward referred to in the offer will only apply to that advance payment. HyperJar is not a party to that contract.