Creating a credit memo after a tax only credit

My business has the below requirement

1. Create a tax only credit memo first, finalize it and send to the customer
2. Create a credit invoice for the same invoice for which tax was credited in step 1. In this step, tax should not be credited again as it was already reverted in the first step. Credit memo should be created only for the amount that was there in the INVOICE_AMT_PRETAX field of the invoice.

We were able to create tax only credits and send to customers

For creating credit memos excluding the tax, we are passing the adjustment rows in INTFC_BI table as mentioned in the peoplebooks (passing TRANS_TYPE_BI as AHDR, ADJ_TRANS_TYPE as CRALL, providing original invoice number in INVOICE_TO_ADJ field). However, when the credit memo was created, it is crediting the tax again which should not happen