Optimized speed version
If you'll compile flightplan without @ symbols the arrival time will be changed by compilator. The arrival time depends on aircraft speed
from aircraft.txt file and orthodrome distance between airport. In fact the route between two airports is not straight
line so average speed for orthodrome should be slower. There're also more factors that 'slow down' an aircraft.
It causes such effect if you comile flightplan UTTT,4/01:35:00,4/04:45:00,360,F,661,USSS with a speed 460, the arrival time will be changed
to approximately 04:04. So the landing of the aircraft will be about 40 minutes earlier (sometimes arrival time could
be more than an hour earlier). Also if you'll load MSFS in USSS at 03:49 aircraft is already near the gate.
Don't you think that 1 hour is tooo much? So it needs to slow down the aircraft to get arrival in 04:45.
In optimized speed version each aircraft has its own speed counted backwards (orthodrome distance diveded by in-flight time) and the arrival
times are closer to times from original timetable. It's not perfect, 'cause every leg has its own speed when MSFS
has speed to all aircraft legs.
The second effect is same flights in different days will arrive in different times because each aircraft now has it's own speed. For example
the flight from above will arrive in 04:40 on mondays, 04:45 on thursdays, 04:29 on fridays and so on... In real
life arrival time is also varies from day to day depending on flight levels, winds, routes and whatever else...
Also I use it to check accuracy of departing and arrival times. If leg speed is more than cruise speed it means time errors (some exceptions
exist for very short routes). 1 flightplan of 3 has such errors like supersonic speeds.