Generate incorrect line amount through API: AR_INVOICE_API_PUB.create_single_invoice

Hi All,
I'm working on Credit Memo generation through API: AR_INVOICE_API_PUB.create_single_invoice

Scenario is AR Total Amount is 10, Line Amount is  8.54, tax amount is 1.46.

However, I'm using the below codes for testing, it would create 1 Credit Memo, tax line is Okay (amount is correct), but line amount is still 10, not 8.54.

And when I press the 'Incomplete' button on the transaction screen, line amount would be changed to 8.54.

Appreciate in advance if anyone can help to take a look it. Application is 12.1.3

Declare

l_batch_source_rec     ar_invoice_api_pub.batch_source_rec_type;
      l_trx_header_tbl       ar_invoice_api_pub.trx_header_tbl_type;