This is normal.
It's because the premium levy is added on the checkout page; moreover, if you choose the annual payment option on the checkout page, the premium is about 10% lower than the monthly option. Annual premiums are paid only once each policy year, so administrative and processing costs are lower than monthly premium payments. We pass these cost savings back to our customers in the form of lower premiums!
What is the premium levy?
According to the "Insurance Ordinance" (Chapter 41), the Insurance Authority has been collecting levy on insurance premiums since the start of 2018 to maintain financial independence. From April 1, 2020 to March 31, 2021, the levy rate is 0.085% based on the premium of each policy year, which means that only HKD 0.85 will be collected for every HKD 1,000 of premium. The rate will be increased to 0.1% from April 1, 2021.