I have a theory of EFC matchmaking system:
You ask for an opponent (quick fight or play again buttons).
Your encounter will be found from top to down of the available players list which are in search of an opponent
Then, on the next fight will occur from down to top of list, followed by top-down, and so on.
The image below explain that. Z palace, C. ring, Z palace, C. ring, Z palace, EFC tower, C. ring, Z palace, EFC ring, Z palace, Polit arena.
Someone please let me know if this stupid system change someday because it doesnt seem attractive to me waste hours and hours of my week jsut to stay at the very same position or fall insanely down to make newcomers happy (just for the moment because when they reach some significant score they will suffer this).