Hi Neuromuscular,
No, we are talking about the same thing.
+'ve stork test (stance phase - where you measure the PSIS and sacrum on the stance leg, not the hip flexion leg)
= unlocking ofSIJ = counternutation of sacrum relative to innominate or anterior rotation of innominate relative to sacrum
In other words, what you described above in your APAS test...
...which simply means stork test +'ve can produce the same results as your APAS test