Employee unable to evaluate Life Event via ESS - Fast formula DBI access?

Summary:

I am using an eligibility fast formula to sum specific assignment working hours to determine eligibility using a loop through assignment history DBIs. This works fine when the life event is evaluated by a benefit admin but when an employee evaluates the life event through ESS, the eligibility fails. Has anybody had this experience? Is it because the employee does not have security access to those DBIs? If so, what are the privileges needed for the employee to be able to successfully evaluate this eligibility formula?

I have been able to resolve this issue using a value set to sum the working hours instead of looping through the assignment records, but I would like to determine if this can be resolved using the original code.