CSV Import to Add Vendor Payments together with Application of Bill Credits generates error response "Adding new line to sublist apply is not allowed"

Scenario:

1. The objective is to import Vendor Payments and apply existing vendor credits simultaneously.

A. Vendor Credits are already posted in NetSuite
B. The CSV file contains the following fields:
--External ID
--Vendor ID
--Payment Amount
--ID of the Bill

--The Payment Amount for the Vendor Bill is positive and negative for the Bill Credit
--Use the Vendor Bill Credit Internal ID  and the Vendor Bill Internal ID on the "ID of the Bill" column

The error will be encountered if:

1. Data Handling is set to Add. This should be Add/Update
2. The Vendor Bill is no longer Open or has already been paid with status Paid in Full
3. The Bill Credit has already been applied
4. The Vendor Bill and Bill Credit do not have the same A/P Account.