please explain

Can anyone explain to me how this is possible...

I continue to accumulate PSA and have had a little order in at 12c for 43235 through Commsec for a few days.

Part of this just got filled:

Time Price ($) Volume Value ($) Condition
1:42:02 PM 0.120 4,500 540.000 XT


However, I am not first in the queue on the rack, I am 3rd:

# Quantity Price ($)
1 30,000 0.120
2 150,000 0.120
3 38,735 0.120

(Commsec highlights my remaining 3rd place units in red to demonstrate, which you can't see here)

I'm only asking this as I am curious as it seems really odd - not really complaining. Will be interesting to see if a further seller at 12 buys my units or those above me... Is it because it's a cross trade?

Feel free to post if you have no interest in PSA, it's a general Q really. Ta