EBTax: Query to list TAX_RATE_CODE based on Operating Unit in R12

In Oracle R12, we have E-Business Tax module to maintain the Tax Details. 

Every TAX_RATE_CODE is attached to a TAX_REGIME and in-turn a TAX_REGIME is tagged to one or more Operating Units. 

Below query is used to list down the TAX_RATE_CODES attached to a Operating Unit.
SELECT hou.organization_id,
       hou.set_of_books_id,
       hou.default_legal_context_id,
       hou.short_code,
       hou.NAME,
       zru.first_pty_org_id party_tax_profile_id,
       zru.tax_regime_id,
       zru.tax_regime_code,
       zxr.tax,
       zxr.tax_status_code,
       zxr.tax_rate_code,
       zxr.tax_jurisdiction_code,
       zxr.rate_type_code,
       zxr.recovery_type_code,
       zxr.percentage_rate,
       zxr.tax_rate_id,
       zxr.effective_from,
       zxr.effective_to,
       zxr.active_flag,
       zxr.attribute3,
       zxr.offset_tax,
       zxr.offset_status_code,
       zxr.offset_tax_rate_code
  FROM zx_party_tax_profile      ptp,
       zx_subscription_details   zsd,
       hr_operating_units        hou,   
       zx_regimes_usages         zru,
       zx_rates_vl               zxr
 WHERE zxr.tax_regime_code         = zru.tax_regime_code 
   AND ptp.party_type_code         = 'OU' 
   AND ptp.party_id                = hou.organization_id
   AND zru.first_pty_org_id        = ptp.party_tax_profile_id
   AND zru.first_pty_org_id        = zsd.first_pty_org_id
   AND zsd.tax_regime_code         = ZRU.TAX_REGIME_CODE
   AND zsd.parent_first_pty_org_id = -99
   AND SYSDATE BETWEEN zsd.effective_from AND NVL(zsd.effective_to,SYSDATE);