I tried to find the Palmer decision on AIPA website but i couldn't find it.
IIRC, the premise is that A pilots are to have 'fair share' rostering. Palmer did this by having the A pilots PSNing amongst themselves. Were the A330 pilots to vote for PSN then that satisfies the requirement of Palmer's decision and thus instead of interleaving between themselves they'd instead rotate with the entire cohort.
Where it gets interesting is if the A330 pilots as a whole reject PSN. Does this then bind the A list pilots too? They were part of the vote and could potentially have vote 'no' if they only wanted to share amongst themselves and didn't want to share with everyone.
I'd have to read Palmer's decision more closely but given I don't have a copy of it.....