To check for left-middle-right AF discreprencies FoCal is a good tool. My experience is that several runs of the same test need to be done in order to get a good feel/measurement of the actual performance. Another, very important issue is to make sure the focus chart is well and stably lit. For the multipoint thest, I've made my own simple focus charts that are at least as good as FoCal's own (see below). The one weakness with the multifocus target from FoCal is the repeated pattern (like an QR code image) which the outer vertical sensitive sensors don't like very much. To check for AF accuracy a simpler tool is just as good IMO. I always do AF tune at a few, typical working distances for individual lenses. Then I compromise to achieve a "good enough" adjustment and save that in the camera's AF fine tuning menu.