The intent of completing a contractor prequalification, is to simplify the vetting process. Should a subcontractor have a current prequalification, via a reputable scheme, we should be able to place a level of reliance on this to support that they have a useful health and safety framework.
ACC’s Experience Rating is the penalty / discount scheme driven by workplace claims. Like your car insurance, if you have no claims, you get a discount and of course, if you have claims, you get a loading (penalty).