The commission is hereby authorized to employ for the term of the commissioners a competent rate expert at a salary fixed by the commission, and an assistant rate expert at a salary fixed by the commission, for the collection of data and evidence for the use of the state in protecting the interest of the state involving duties and obligations of all common carriers, all common carriers by motor vehicle, all restricted common carriers by motor vehicle, and all contract carriers by motor vehicle, and for the establishment of proof in litigation now pending or which may hereafter be instituted.

The rate expert and his assistant shall make all needed investigations affecting rates and rate making and shall perform such other duties as the commission may find necessary for them to do in the interest of the state.

Said duties shall also include the checking and investigating of the filing of rate schedules with the commission, and making of reports to the commission respecting tariffs filed by any of the above-mentioned carriers with the commission involving the increase of any rates for movements within the State of Mississippi, and the general checking and reports to the commission affecting any rates increased from points without the State of Mississippi to points within the State of Mississippi, and from points in the State of Mississippi to points without the State of Mississippi. Said rate experts may be discharged by the commission for incompetency or other good cause, but they shall have notice and an opportunity to be heard in respect to any charge for removal.