Upon further replicate using my TSTDRV account, here’s what I did.
- In NetSuite UI, I have created a Bill record with Installment, ID: 3810

- Using oa_columns, I have tried to query a specific sublist to further check the table location. With this, I have noticed the
VendorBillInstallmenttable
select * from oa_columns where column_name = 'amount';

With all of the test, I came up with this query
select * from VendorBillInstallment where vendorbill = '3810';

Hope this clarifies your concern.