I can only speak for BSAC.Was aware that there were some top ups needed, but suprised Deco and Nitrox are in there - aren't they taught in AOW or Rescue? BSAC introduce nitrox (up to 36) at Ocean Diver level (OW equivilent), and introduce deco in Sport, so if AOW and Rescue don't cover them seems to make a bit of a mockery of equivilencies.
The equivalents listed be BSAC are the minimum requirements to start training to the next level.
For example, a PADI AOW would have to complete Nitrox and basic lifesaving in addition to the Sports Diver course.