Vacation Purchase

[Guest JeffG]

Does anyone know if the regs require all nonelective PTO time to be used before all elective PTO even if the plan only allows paid vacation days, for example, to be purchased. In other words, if an employee buys 40 hours of "paid vacation," does he or she have to use all nonelective paid sick time in addition to all nonelective paid vacation time before using the elective paid vacation time. Thanks.