One thing to keep in mind is that AF with any methodology has a distribution of errors. Whether you are using Live View and contrast detect (CD) or using phase detect (PD), there is still a distribution. You can still get missed focus with either method, and every time you focus will be slightly different.
LensRentals.com has done some testing on this and found the distribution is getting tighter and the difference between PD and CD methods is shrinking significantly. They also found that lens selection makes a difference - and the newest lenses tend to produce better results with PD coming closer to CD.
As we move from the center sensor to other cross sensors, and on to regular sensors, AF consistency falls. It's going to fall with phase detect more than Live View since Live View is using contrast detect.