Why is there a reduced contribution limit to the Dependent Day Care FSA if you are a highly compensated employee?

XPO is required to perform tests on the Health Care FSA and Dependent Day Care FSA to ensure the accounts do not favor participants who are considered highly compensated under federal tax law. If the tests are not satisfied, pre-tax contributions of higher paid employees may be reduced. If a reduction in pre-tax contributions is necessary, the plan administrator will notify the affected employees.