Unless you are doing W's with short flight times operating with the same crew, you could, when on 3 or 4 sectors soon run out of FTL hours once you cop a delay,
which at places like Palma or Corfu in the summer you are always at risk of.
If IIRC, you Roster a Crew to report before 0600 your available FTL hours then become very limited when operating a 3, or even a 4 sector day.
I know the FTL Regs and Rules have changed a fair bit since my day but it's still limiting.
You had much more leeway with a Crew reporting after 0600.
At Monarch we had an 0655 departing from LGW to Mykonos, thus the crew report was before 0600.
At that time the runway was too short on the Island for flying non-stop back to LGW so a fuel stop was made at Athens making this a 3 sector day.
On many occasions due to ATC and/or other operational delays down route, the Crew would have to agree to go into 'Discretion'.
Once a twice that did not happen and the Flight had to stay at JMK or ATH, the Passengers had to go to a hotel, whilst the Crew took minimum rest.
At BMA the Crews would be rostered for 3 x MME-LHR DC-9 round trips and still be ''in hours'' (6 sectors)
The Crew reported at 0630 and were off duty back at base (MME) at 1530.
BD331/332 Hot breakfast, BD333/334 Light meal, and BD335/336 Hot lunch.
Hard work, and the 331 and 332 were always full (up to 92 Pax).