Yup! You have it right!
Just to remove one slightly lingering doubt from one of your comments, I quote your comment with the worrying word emboldened, and my suggestion for revision with my suggestion also emboldened -
"FMC will fly a Great Circle track from point A to Abeam point B and another Great Circle Track from abeam point B to point C and the distance travelled is THE SAME as the Great Circle Track from point A directly to point C ?"
Changed to -
"FMC will fly a Great Circle track from point A to Abeam point B and CONTINUE ON THE SAME Great Circle Track from abeam point B to point C and the distance travelled is THE SAME as the Great Circle Track from point A directly to point C ?"
Just being pedantic to be absolutely sure!
Whilst still in pedantic mode, you mentioned Latitude change as the primary cause of GC continuous Track change. Actually it is a combination of Latitude
AND Longitude if you revert back to the basic Spherical Trigonometry computations.
BTW, The map projection displayed is Antipodeal Stereographic, which can make some straight lines look 'bent' at times. Gnomonic would be better in this respect, but presents unacceptable scale expansion at greater distances.
Regards,
Old Smokey