When ICBC UnionPay Dual Currency Credit card says they will give up to 8% cash back on purchases, how real is it?

Cardmembers will earn 0.5% Cashback on all Qualifying Spend up to the amount of S$500. Cardmembers who spending more than S$500 for three consecutive months within the Promotion Period will get to enjoy up to 8% Cashback on the amount above S$500.

For example: If you use your UnionPay Credit Card to spend more than S$500 for every month of the Qualifying Quarter, in the last month of the Qualifying Quarter when you spend S$570, you will enjoy 0.5% Cashback on S$500 and 8% Cashback on S$70.