From the link provided under definitions, 1.1095, page 192:
Flight Duty Period:
A Flight Duty Period (FDP) is any time during which a person operates in an aircraft as a member of its crew. The
FDP starts when the crew member is required by an operator to report for a flight or a series of flights; it finishes at
the end of the last flight on which he/she is an operating crew member.
So from check-in to last on-block is correct.