On the Third Party Billing screen, you can mark a batch to post. This will cause the batch to automatically post after hours. This feature is useful if you have many batches to post, or the batch is large, and do not want to wait using the "Post" option.

Select the Mark for Post option

Marking the batch to post will cause an icon to show for the batch

A process will run overnight to pick up any batches marked to post, and post them into accounting.