Does Sage allow posting of one-sided entries?
No. The Sage300 program is based on generally accepted accounting principles and one-sided entries cannot be posted. If a one-sided or unbalanced entry is saved in a GL batch and posted, it will be kicked out into an error batch where it can be corrected and then reposted.
In some modules, such as Bank Services, it appears that one-sided entries are allowed. However, when a user enters a bank entry, they are only entering half of the entry; the other half (unseen on the screen) is to the bank account designated by the bank code. This full entry can be seen in the GL batch when the transaction is sent from Bank to GL.