Not sure what the need for the flight plan has to do with it. Has the schedule the Commander showed up for been published. That's really all that is needed. Any Charter Pilot will then tell us if the block times are kosher (the turn round of 45-60 mins).
I guess the other question is what are the implications now for TC crews in the future. On the same flight next season will a extra crew be sent down to operate the last sector (on the aircraft even?). Will the crew that Pax back on the last leg say "i'd rather operate" than sit down the back with the punters.....