The collection agency may charge Chambers County for collecting the tax levied under this part in an amount or percentage of total collections as may be agreed upon by the collection agency and the Chambers County Commission. The charge shall not exceed two percent of the total amount of the tax collected in the county if collected by the Department of Revenue or the actual cost of collection, whichever is less. If collected by an entity or agency other than the state, the collection charge shall be two percent of the tax collected in the county. The charge may be deducted each month from the gross revenues from the tax before certification of the amount of the proceeds due Chambers County for that month. The collection agency shall pay into the Chambers County General Fund all amounts collected under this part, as the tax is received by the collection agency within 10 days after it is collected. The collection agency shall certify to the county commission the amount collected and paid into the General Fund of Chambers County during the month immediately preceding the certification.