Is there a difference in an audit if I use a Certified Service Provider (CSP) or a Certified Automated System (CAS)?
Answer:   If you contract with a CSP and you are a “volunteer seller”, the states will generally contact the CSP for any audits or questions concerning your returns and tax payments. If additional documentation is required, the CSP will contact you for that documentation.  The purpose of the Streamlined Agreement is to reduce the burden of tax compliance for you, which includes reducing the number of auditors at your business.   

If you use a CAS, the state will conduct the audit with you at your place of business.