A321 flight crew took off from an unauthorized intersection due to a failure to scrutinize the takeoff performance data completely.

Narrative

Takeoff was planned between departure end of Runway 9L and intersection of taxiway K5. Weight and balance data received while pushing back from gate. The First Officer noted that no data was sent for Runway 9L. He contacted load and requested 9L data. I reviewed the original data while we were being pushed. I noted that our ramp weight was approximately 3000 pounds less than originally planned. We taxied single engine to Runway 9L. Tower asked if we were ready and we stated that we needed a little more time. We were at the intersection of K5 and Runway 9L. I asked the First Officer if we were legal for the intersection and he said yes. The original weight and balance had stated that we were not; however we were 3000LBS lighter than planned so I accepted the First Officer's assurance. Tower cleared us for takeoff. The First Officer performed the takeoff without event. Later in the flight I reviewed the weight and balance sheet and noticed that the intersection we departed from was listed as not authorized. This event occurred because the entries on the final weight and balance were not verified by both crewmembers reviewing the weight and balance sheet. Our procedure changed months ago as to where the Captain did not have to review the sheet anymore. As practice I do review it however due to workload and distractions I did not do it this time. Unfortunately the First Officer did not read/enter it correctly and I did not catch the error. Task loading was extremely high! Change the takeoff data verification procedure to have the Captain review the weight and balance sheet. When task loading is that high be more vigilant.