It's specifically directed to cargo in the cabin area. Bottom line is if there are no OEM instructions in RFM to secure cargo in cabin area, then the operator must obtain approval from FAA to do that via a major alteration or install a OEM kit that comes with the RFM supplement to do so. There is a factory SB to install cargo provisions in a 350. In this this case, had the operator followed the requirements of a major alteration, even though they exceeded the floor max load, the dog boxes probably won't have broke free as the install would have been load checked at a minimum of 3x the max weight. Now whether this would have prevented the outckme is unknown.