Yes, you are right.
vouchers in period 0 are created uniquely by final year-end process. 

If you want to adjust opening balance of one year, you should do adjustment in period 13 (closing) of previous accounting year

Thanks for yoir help

Hello, 

My customer will soon start using an internal ledger for the first time; for IL opening balance to be uploaded on all account types (ledger accounts etc) , could I use the same process you described ? 

I’d create a Q voucher on period 13 of this year on the Internal Voucher Entry window, to ensure balances are transferred to period zero of next year through the year end process? 

Thank you for your help

Tanya