All insurance carriers authorized to write workers’ compensation insurance shall make available, at the written request of the employer, a workers’ compensation insurance rate containing a deductible provision which shall bind the employer to pay, at a minimum, 100 percent of the first $500 of benefits due to an employee, whether these benefits be medical benefits or indemnity benefits. The commissioner shall approve rates that include larger medical and indemnity deductibles on benefits greater than $500. The commissioner shall prescribe the maximum medical and indemnity deductibles. Employers who choose to acquire workers’ compensation insurance with a deductible provision, as to the amount of the deductible, are considered insurers and shall have the same responsibilities under the applicable sections of RSA 281-A.