ams511
Contributor
The point being, if the holes are consistent amongst brands, then a Single Tank Adapter (STA) allows those brands to be mixed & matched to your heart's content.
The clue is in the name: "adapter".
The benefit of sticking to a single brand, or researching compatible brands, is that the diver may not have to use an adapter (directly thread cam-bands through the backplate and wing). There are benefits for lighter-weight rigging/travel with that option. The benefit to using an STA is 'universal fit', plus the addition of well-trimmed weight that may be needed.
The point is you are now changing your story because you know I am correct. In post 21 you said you did not assume a single tank adapter was necessary to mix and match different brands of wings and plates but now you do.
The purpose of a single tank adapter was to take a backplate that was originally made for doubles and allow it to be used for singles. Early plates did not have slots cut into them for the cam bands. The single tank adapter was not developed to mix and match different plates and wings although it can be used for that purpose. Some divers like using an STA because the feel the tank is more stable or they want the extra weight an STA provides. Other divers do not like it because the tank is mounted further away from the diver.
A diver does NOT need to stick with a single brand in order to eliminate the single tank adapter. They just need to make sure the slots line up between the plate and the wing.