Also, you don't know exactly what kind of fermentablility you are getting out of the extract. You are sitting at about 66% attenuation right now and WLP001 should average 75% but who knows. That is why it is hard to brew a dry beer with extracts where you can control your mash temp to create super fermentable wort by mashing low.
It sound like you have done everything right with your starter and oxygen and such, it may be the sugars problem.
my pliny beer went from 1075 to 1010 but I mashed at 149 and used 1 vial of WLP001 on a starter.
On tap: #79 Berliner Weisse 1.030 9/20/12, Flanders, Barleywine, Wild Blonde (1.045 blonde hopped up and fermented with WLP644), #80B rett Saison
Fermenting: #82 Galaxy IPA, #83 Black IPA
Aging: #67 Bareleywine 1.116 11/07/2012, Flanders 2 batches 1.056 and 1.060 12/12/11 and 3/26/12, Kriek, 1.052 12/11,