When an employee is working light duty on a part-time basis or full-time basis and earns less than he or she would be earning if employed in the full capacity of the job or jobs, then the employee is entitled to temporary partial disability benefits. Temporary partial disability benefits are equal to two-thirds of the difference between the average amount that the employee would be able to earn in the full performance of his or her duties in the occupation in which he or she was engaged at the time of the accident and the gross amount which he or she is earning in the modified job provided by the employer or in any other job that the employee is working. 820 ILCS 305/8(a).