The command /tickingarea will place a ticking area at coordinates not even listed in the command.
MCPE-169635
Command /tickingarea Faulty
Resolved
Invalid
0
The output of your command is correct. 8x 8y is the horizontal center of the chunk in which you ran the command. Ticking areas always show 0 Y because the Y value is not applicable. Chunks, and therefore ticking areas, go from the bottom to the top of the world.