The director may fix a daily rate to be expended for such convict labor, and when so fixed, the agency shall monthly set aside funds to the director to pay for such labor, and where no funds are available from the agency the director may set aside the department’s own funds to pay for such labor. The director, by regulation, may authorize any or all deductions to be made from the pay due convicts as provided for convicts at road camps under Section 2762. The director, by regulation, may also fix the maximum amount, over and above all deductions, that a convict may receive.