“Interest at the current rate” means that amount of interest which would have been credited to the account of the member on the amount to be deposited at the interest rates established for the system if the contribution required by that section had been on deposit from the time he became a member of the system until the amount required to be deposited has been paid.
Source:
Section 31641.51, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV§ionNum=31641.51..