Really you made a post about this? lol
You should go back and read the dictionary post I made as it said BOTH are correct, Foci AND Focuses.
Maybe you should go back and reread some of the posts, I'm not giving a test.
BTW I was a copy editor from 1988 to 1991 for the military, I have a little bit of a background in the field, not much but some. I have been corrected by some of the best copy editors in the US Army, I can take it, it's part of the job.
2001 Focus ZX3 Race Car in Germany-Ours
2010 Renault Clio 1.2 16V in Germany-Hers
2004 SVTF EAP/ST170-Mine
2013 Focus ST2 TS NAV SUNROOF-Hers