A. If the injured employee's date of injury is prior to January 1, 2013, partial benefits are calculated at a rate of 80% of the difference between the employee's after-tax average weekly wage before the injury and the after-tax average weekly wage that the employee is able to earn after the injury, but not more than the maximum benefit under section 211. To calculate partial benefits: 1. Determine the 80% rate for the employee's pre-injury average weekly wage using the Weekly Benefit Table in effect at the time of the employee's injury.2. Determine the 80% rate for the employee's post-injury weekly earnings using the Benefit Table used in step 1 above.3. The difference between the post-injury rate and the pre-injury rate is the partial benefit amount.B. If the injured employee's date of injury is on or after January 1, 2013, partial benefits are equal to 2/3 of the difference due to the injury, between the employee's average gross weekly wages, earnings or salary before the injury and the average gross weekly wages, earnings or salary that the employee is able to earn after the injury, but not more than the maximum benefits under section 211. To calculate partial benefits: 1. Determine 2/3 of the employee's gross average weekly wages, earnings or salary in effect at the time of the employee's injury.2. Determine 2/3 of the employee's post-injury weekly earnings.3. The difference between the post-injury rate and the pre-injury rate is the partial benefit amount.90- 351 C.M.R. ch. 8, § 8