Pentax K30 or Canon 60D?

Yes, that is correct. The optical path coming into a DSLR camera diverges at the mirror. Part of the light goes to the AF sensor and part goes into the focusing screen. These light paths must optically match the one that goes to the sensor when the mirror flips up. If the mirror or the AF sensor position is off, by a tiny bit, the camera will not PDAF properly.

CDAF uses the info coming straight from the sensor, so it will be relatively foolproof. The camera moves the lens to maximize contrast coming off the sensor in the focusing box that you (or your camera) has chosen. This focus box can usually be made larger or smaller and moved around most anywhere in the frame. On DSLRs, the focus point are in fixed locations chosen by the manufacturer.