So a while back, I emailed this question to the FSSP and today I received an answer from a vocations director there. I won't mention names and he admits he's not a canon lawyer or even a priest, but this is the response I received:
"In the matter of Ordination, the laying on of the hands of the Bishop constitutes the matter of the sacrament. The form that follows has been modified from time to time, and is incidental to the ceremony and sacrament. Hence, as long as the succession of the apostles is carried forward by the laying on of hands, the Ordination is proper, valid and full. Our human desire for ceremony and solemnity has most likely brought about the beautiful and consequential forms of our liturgies – and cultural tastes have also dictated their amplification and their simplification.
Hence, there are no grounds to believe that this Pope or that Pope, this Bishop or that Bishop, or this Priest or that Priest, has not been validly ordained, unless the MATTER of the sacrament was not performed properly. In most cases there are numerous witnesses, both clergy and laity, who have observed and witnessed the ceremony, and can vouch for the proper matter being conferred on the ordination."
I must admit that this doesn't seem right to me either. It almost sound like the form of a sacrament is irrelevant. Maybe that's not what he met, but that's what it sounds like.