How to calculate "duty" when between flights in a 135 operation Here is the scenario ... at 6:00am pilot flies from Location A to Location B to drop off a customer.  Flight duration is 2hrs.  Pilot is then given the day to do with as they want to but must be ready for the return flight at 22:00 later that day.  The return flight is another 2hrs.

Question: Has the pilot exceeded their daily duty limit under part 135 rules?  Or is it reasonable to assume the interval between flights would constitute a 10hr rest period? 

NOTE: between the time of 8:00 and 22:00, the pilot was not paid and able to do anything they wanted with their time.  They were not expected to wait at the airport and knew they would not be needed before 22:00.
I have not checked the latest regs, but the time beginning at the point where the pilot is done with all postflight duties until the time the preflight duties begin (ex. checking weather) is considered rest time ONLY IF the pilot is really off the clock.  If the company requires anything of the pilot (ex. "stay near the plane...just in case"), it is not rest time.