Detailed records shall be kept of all investments made directly by the local agency in a subsidiary investment ledger. A specimen ledger sheet which reflects the procedures described in this Part, is appended as Exhibit 1 of Appendix S-10. A separate sheet should be maintained for each lot, by type of securities, acquired. For example, if $10,000 maturity value series F bonds, and $20,000 series G bonds were acquired on May 1, 1956, separate ledger sheets would be set up for each lot. If $5,000, maturity value, series F bonds were acquired at a later date, a separate ledger sheet would, similarly be set up. The ledger sheets should be segregated by the funds and each investment of reserve funds should, further, be marked for the particular reserve to which the investment is applicable. The investment ledger should, at all times, reflect the current book value of each investment and the sum of the balances should agree with the balances in the general ledger investment accounts (1170 group). The investment ledger should also reflect the current balance for interest receivable on investments and the sum of the balances should agree with the general ledger accrued interest account (1144).