They are (rightfully) ticked off that the deal changed after the 717 went away. They bid thinking that they were staying on the property much longer than they are now. Making up for their loss of pay due to much lower line totals until 1/1/15 isn't too much to ask for, IMHO.
As for the possibility of redoing the list via arbitration.... The AT folks are not bringing anywhere near as many seats to the party as they were when "we", overwhelmingly, agreed to this SLI.
Supposing we go to arbitration to redo the SLI, then wouldn't the lack of 717s be considered by the arbitrator too? What % of the AT fleet was comprised of 717s? More than 51%?
Would Bond McCaskill have even been a consideration if we knew about the 717s going away before the SLI?
Oh, and PCL, why do you even care? You're not coming over anyway, right?