Currently the lock date is preventing from posting transaction before the set up date, however they can still modify invoice date and change it to future period consequently changing month end balances. As an example, if lock date is set up as 30/06/24, the user with restricted rights cannot post anything to June, but he can change June dated invoice to be dated 01/07/24 which takes cost from June and move to July and this change June balances after month end being processed.