Table with hall sensor output voltage relative to phase voltage (aka six step configuration - current step). Zero phase voltage indicates that phase is not driven by transistor half-bridge.

Visual representation of table above.

Hall sensors seem to be aligned in such a way that when any of hall outputs change state, commutation event shall occur (sometimes referred as 0° orientation with respect to phase zero crossing):

Im not sure what is the benefit but apparently the other option might be 30° orientation (not relevant for this motor):

Source: Texas Instruments - SLAA695.