I went through AFF in Antioch, CA in 1985 and my student rig was equipped with an FXC12000. On my 3rd level AFF jump the manafest lady checked to make sure I put on my gear correctly before being turned over to the instructors. She set the FXC by just turning it to the opening altitude. On the jump the thing fired at 9,000ft giving me a long canopy ride. I was told on the ground that the correct way that the FXC should have been set was: 1) to zero it and then 2) set it to the desired opening height.