A couple of things might impact you.
The credit score as of the date of the report if it was say an A category might tell you that statistically over the next 12 months 99.xx% - or some number like that - will keep their commitments and pay their obligations to credit providers. They mean - make payment by 90 days from the date it is due.
They calculate this for each level of rating. It groups credit users and calculates their statistics. OP might be in a group that statistically only pays on time 54% of the time (just a wild number based on nothing as I have NO idea what it is for E). Even though OP is a good bill payer he is scored based on maybe his mortgage to income lower as a risk.
From TransUnion site:
Q What type of information is used to generate my credit score?
A basic scoring formula uses several elements of a credit report:
Payment history - Accounts with a history of on-time payments are considered valuable assets that will boost a credit score.
Outstanding debt - High balance-to-credit-limit ratios may lower credit scores. Maintain reasonable balances on available credit.
Credit account history - An established credit history makes you a more reliable borrower.
Recent enquiries - When a credit provider checks your credit, it implies that you may be taking on additional debt. As this slightly reduces your credit score, apply for new credit in moderation.
Public records - Public records (including bankruptcies and legal actions) may negatively affect a credit score. All public records are kept on your report for seven years; bankruptcies, eight years.
The existing credit score in Hong Kong is largely based on: credit account information, account delinquency data, credit enquiry, history data and public record data.