I display many symptoms of AvPD without having severe social anxiety (mine is probably mild, maybe even lesser) or being agoraphobic. I really believe I'd get diagnosed with both too, though. But I don't believe they are the same thing, at least that's not how I experience them. That's why I also made a thread about this a while ago, but it ended up being deleted.

AvPD affects your interpersonal relationships in a deeper level than SAD. Not everyone with SAD have problems making connections or getting close to people in a personal 1X1 level, for example. My SAD is triggered by specific events, while my AvPD symptons are constant and wide, like a chronic thinking. AvPD is mostly not only about feeling anxious towards people, but believing in things like being inadequate or subpar or being simply tolerated or really disliked by people. It also happens not only in one single aspect of your life, but life in an overall way.

On a sidenote, it's very likely something will come out of online tests specially if you're young AND already diagnosed! Don't get distressed by that!