B737 OVERSHOOTS ASSIGNED ALT DEPARTING LAX WITH SCT TRACON.

Narrative

ON DEP CLB TO 15000 FT; AUTOPLT ENGAGED. SOCAL CALLED TFC AT 11 O'CLOCK AND 16000 FT. WHILE IN TURN TO LAX VOR ON COURSE AND CLBING (APPROX 250 KTS); FO ALERTED CAPT (FLYING) OF EXCESSIVE RATE (2000 FPM) PASSING 14000 FT FOR 15000 FT. CAPT MANUALLY ASSISTED LEVELOFF; THEN DISENGAGED AUTOPLT AND PUSHED ACFT OVER STOPPING CLB AT 15500 FT AND THEN CORRECTED BACK TO 15000 FT. NO TCASII ALERT. NO COMMENT FROM CTLR AS WE PROCEEDED ON TO OUR NEXT CITY NORMALLY. ACFT WAS NEW -700 WITH WINGLETS WITH LIGHT (50 PAX) LOAD. CLB PERFORMANCE WAS IMPRESSIVE. I HAVE FLOWN THIS DEP MANY TIMES AND HAVE NOT HAD AN ACFT FAIL TO AUTO LEVEL WHILE CLBING. I FLEW 3 MORE FLTS WITHOUT ANY OTHER AUTOPLT PROBS. NOT SURE WHAT CAUSED THIS 500 FT OVERSHOOT. AUTOPLT WAS DEFINITELY ENGAGED AS THE DISENGAGE ALARM WAS HEARD. GOOD CREW COORD PREVENTED IT FROM BEING WORSE AS THE PLANE DID NOT ATTEMPT AUTO LEVEL PRIOR TO AUTOPLT DISENGAGEMENT. IT IS EASY TO GET COMPLACENT WITH 'HAL' FLYING. A REMINDER THAT WE MUST ALWAYS BACK UP 'HAL.' QUESTION: COULD THIS ACFT'S PERFORMANCE EXCEED THE AUTOPLT'S CTL PARAMETERS?