Group 1 - The calculation of the supplementary payment is based on the formula: (new payment base for 2025 - original payment base) × payment ratio × number of months already paid [3] - The payment ratio for flexible employment pension insurance is set at 20% [3] - If the supplementary payment is not completed by December 31, 2025, it will affect the future pension calculation [3] Group 2 - To avoid payment errors, it is important to use specific channels such as the electronic tax bureau APP or official WeChat accounts [3] - Before final payment, it is crucial to verify the payment amount, payment period, and insured person's information [3] - Payment records can be checked through the electronic tax bureau APP, Sichuan Human Resources APP, or tax service halls [3] Group 3 - In case of issues during the payment process, it is advised to save all successful payment receipts and contact official channels for resolution [3]