MD80 FLT CREW HAS A CLOSE IN RWY CHANGE ISSUED DURING THE SEAVU 1 ARR TO LAX.

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ONCE AGAIN; ON THE SEAVU ARR TO LAX WE WERE GIVEN A LATE RWY CHANGE. THE ASSUMED RWY FOR LNDG FROM THE E IS RWY 25R AND THIS WAS PROGRAMMED INTO THE FMS. AFTER PASSING KONZL INTXN WE WERE HANDED OFF FROM LA CTR TO SOCAL APCH. SOCAL CLRED US TO DSND VIA THE SEAVU ARR FOR RWY 24R. REPROGRAMMING THE FMS FROM RWY 25R TO RWY 24R CAUSED THE INTERMEDIATE WAYPOINTS OF CATAW AND SEAVU TO DROP OUT; AND THE AIRPLANE BEGAN A TURN DIRECT TO DIXXN. RECOGNIZING THIS ERROR; WE WENT TO HEADING SELECT; SCRAMBLED TO REINSERT THE WAYPOINT CATAW; AND RECOMPOSED THE CORRECT COURSE. THE SITUATION IN THE COCKPIT WAS TOTAL HEADS DOWN CONCENTRATION ON COURSE RECONSTRUCTION WHILE DSNDING BELOW 18000 FT IN CAVU CONDITIONS. I WILL ADMIT THAT RELIANCE ON VOR NAV WOULD HAVE RENDERED THIS DISCUSSION MOOT; BUT OUR GOAL FOR THE FUTURE IS TO RELY SOLELY ON FMS. AS LONG AS THERE ARE ANOMALIES IN CHANGING RWYS FOR INTENDED LNDG OR TAKEOFF IN CONJUNCTION WITH SIDS OR STARS; ATC MUST WORK WITH US AND GIVE US ENOUGH TIME TO MAKE THE APPROPRIATE CHANGES TO OUR NAV COMPUTER. A RWY CHANGE ON ARR AT LAX INSIDE KONZL IS NOT ADEQUATE! WHAT WILL IT TAKE TO MAKE SOCAL REALIZE THAT!