B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 308
Time Pressure; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Undershoot; Deviation - Altitude Crossing Restriction Not Met; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance
Human Factors; Procedure
While on the SEAVU Arrival and just inside KONZL at 17;000 feet; we were told to descend via the SEAVU Arrival for 25L.  We had set up for and briefed 24L.  I've been in this situation before like many of us have been; so I did like the Reference notes suggest.  Page one describes if you are outside of KONZL; and page two advises if you are inside of SEAVU.  Problem was I was inside KONZL.  Nonetheless; I did as it recommends:  I selected SEAVU Arrival; transition and runway (which gave me a route discontinuity).  At this point I'm behind; high and trying to program the FMC.  In short; by the time we had everything programmed and reconnected; we were slightly off course and were instructed to intercept the Localizer after GAATE. We could have Verbalized; Verified; Monitored and Intervened better as a Crew.  However; ATC puts an undue burden on Crews at this point on the arrival to have to program the FMC and be heads down at a busy time.  ATC needs to issue a runway prior to us starting the arrival and if they can't (or have to change runways on us well into the arrival); the burden needs to fall on ATC to get us back into position with more simple means: i.e.: a vector to intercept; or direct to a fix on the approach.  Sometimes in situations like these I feel we are there to make their jobs easier; instead of the other way around.  In the future; I will say; unable; and request a vector or direct a fix.
B737 Captain describes a runway change during the SEAVU 2 arrival to LAX that results in some altitude and track deviations when the FMC is switched from 24R to runway 25L.