first you quoted 380 then 330 then gave a reference to 300!
lets look at the reference, which doesn't seem too add up either
it quotes a total salary paid by all clubs off $200.2M. This figure includes items above the cap, presumably is for all players on any list (e.g rookies, b-rookies), sydney's cola, gws and suns temporary excess allowances and older veterans discounts, etc)
the number of players would be 44 x 18 = 792. Let's make it 800 to include b-rookies and gws, suns extra lists.
now $200.2M / 800 = 250k average, so I still can't see where they came up with 300 without being selective of some figures somewhere.