Typically, administrative fees charged by ASO's range from $600 to $1800 per employee per year on average but like the PEO, these fees can vary based on the services included within the ASO arrangement. ASO vs. PEO - Apples to Apples Cost Comparison.lthough the ASO and PEO can be similar in services offered, the cost difference can be significant depending upon the services included. Typically, the ASO can cost less than the PEO for similar services but keep in mind that you will retain all liabilities and repsonsibilities for compliance.