Concerning the "Workers' Compensation Act of Colorado", and, in connection therewith, making changes that affect the timely payment of benefits, guardian and conservator services, offsets related to the receipt of federal disability or retirement benefits, the apportionment of benefits, the selection of independent medical examiners, limits on temporary disability and permanent partial disability payments, the withdrawal of admissions of liability, mileage expense reimbursement, the authority of prehearing administrative law judges, petitions to review, the reopening of permanent total disability awards, and appeals to the court of appeals.