The Answer is NO.
The FSLA (Fail Labor Standards Act) does not require that PTO hours(like vacation, sick and holiday) hours be counted into weekly overtime calculations for nonexempt employees. The reason that time off hours should not be included in overtime pay is that the hours are not actually worked. Only hours actually worked must be counted when calculating overtime pay.
PTO Hours VS Worked Hours
Worked hours are defined as time spent on the clock, when the employee is clocked into work and performing day to day activities benefiting the employer. PTO(or time off) hours are defined as hours counted toward payroll, but are not actually worked, these typically include vacation, holiday and sick time. PTO hours are typically part of the employee contract as a benefit to the employee, essentially a gift from the employer to the employee. There are a few exclusions, see here for more info.
Can An Employer Include PTO For Overtime
Yes. There are no regulations stating than an employer cannot include time off hours into overtime, this may be a benefit to the employee and may be done at the employers discretion.
An Example Of PTO & Overtime
Assumptions: Overtime is due after 40 hours per week
If during a work week, an employee worked 4 days at 9 hours per day(4 X 10 = 36 hours). Then took 8 vacation hours on Friday this would give a total of 44 hours for the week. So we have 36 worked hours and 8 PTO hours. Overtime would not be paid in this circumstance.