I believe this FDP ending with ON CHOCKS is rather in line with CAP371 a UK publication pertaining to FTL. Whether the rest of the FTL actually follows it 100% I am not too sure - Mach you will have do do some matching and research.
From what I gather - FDP affects the current flight directly and once the chocks are on - the flight is deemed to have completed. Whereas your rest period affects the ensuing duty and thus includes the 30 mins or whatever airline agreed post flight as part of the duty - this will determine the rest that you require prior to operating again.
FDP and Duty are different. One is used for Flying and the other used for Rest. A lot of Major Airlines certainly follow this scheme or close to it with variations based on Operator requirements - these normally are worked out with Regulatory Authority and Pilot body/Company.