One element that firgures into this is local custom.
As much as possible, I try to attend pre-55 Holy Week liturgies. From my own experience, whether pre-55 or 62, I have witnessed congregations that kneel for the Good Friday Collects and congregations that genuflect for these. One year I attended a Good Friday where the prayers were so fast that one had no time to do anythong between the "Flectamus genua" and the "Levate".
The point here is that things can and do varying from place to place. When in Rome... but when in Rancho Cucamonga...