Question regarding wsh_new_del_interface and wsh_del_details_interface

I want to understand how and when records get processed through these two interfaces - wsh_new_del_interface and wsh_del_details_interface.

We have had situations where records are stuck in these two interfaces and we are not able to ship te deliveries through our third party application that we use that interfaces with Oracle. I am not sure at this point if it is a custom validation that we have to make sure there are no records in these interfaces before we ship confirm or if this is standard validation.

Any help would be much appreciated.

Thanks,