Pagibig MP2 Question

Hi! I invested about 20k in my mp2 account in January 2023 which was accumulated monthly with 9k starting on January 2023 then 1k per month after. Then I wasn't able to put any money in the whole year of 2024. Why is it that my 20k + interest remained the same since getting the 2023 interest? Is the interest for 2024 not applicable to my current 20k+ 2023 interest? Does that mean the interest for the specific year is only applied to the contributions made for that year only? Thank you!