ALTDEV DURING APCH.

Narrative

ARRIVING FROM THE N; APCH CTL ADVISED US TO EXPECT AN ILS RWY 24R. ON DOWNWIND; HDG 070 DEGS; FOLLOWING A 747; WE WERE TOLD TO CHANGE PLANS FOR AN ILS RWY 25L AND MAINTAIN 3500 FT. AT THAT TIME; I ADVISED OUR CTLR THAT WE HAD POSITIVE VISUAL CONTACT WITH THE 747 AHEAD. VECTORS TO THE SE; THEN S; THEN SW TOOK US OVER THE APCH PATH OF THE 747; WHICH WOULD BE LNDG ON RWY 24R. CTLR ADVISED US TO MAINTAIN 3500 FT TO HUNDA. I DO NOT RECALL IF WE HAD BEEN CLRED FOR THE APCH YET. A 220 DEG HDG VECTOR PUT US THROUGH THE RWY 25L LOC TO THE S. WE WERE THEN GIVEN A 270 DEG HDG TO INTERCEPT THE RWY 25L LOC. AT A POINT APPROX ABEAM HUNDA; MY FO BEGAN A NORMAL APCH DSCNT FOLLOWING GS GUIDANCE. A MOMENT LATER A DIFFERENT APCH CTL VOICE ASKED US OUR ALT. I REPLIED 3000 FT. CTLR THEN SAID; 'MAINTAIN 3500 FT UNTIL ON THE RWY 25L LOC.' WE EASED BACK UP TO 3500 FT; MOMENTARILY THEREAFTER INTERCEPTED THE LOC FROM THE S SIDE; NOW INSIDE HUNDA AND 2 DOTS HIGH ON THE GS. I INFORMED THE CTLR WE WERE ON THE LOC AND ASKED IF WE WERE CLRED FOR THE APCH. CTLR CONFIRMED THAT WE WERE CLRED AND SWITCHED US TO TWR. THERE WAS NEVER ANY CONFLICT WITH THE 747 ON RWY 24R AND I DON'T THINK APCH GOT OUR VISUAL CALL ON THE 747 EARLIER IN THE DOWNWIND. WE MAINTAINED VISUAL WITH THE 747 UNTIL APPROX 2400 FT 2500 FT ON THE APCH. A FOLLOW-UP TELEPHONE CALL WAS MADE BY ME TO SOCAL APCH AT THEIR REQUEST. HOPEFULLY; THE MISUNDERSTANDING WAS MUTUALLY RESOLVED BY THAT CALL. I FEEL THAT IT WAS. SOCAL APCH IS ONE OF THE VERY BEST APCH FACILITIES THAT MY AIRLINE WORKS WITH. I PROBABLY SHOULD HAVE ASKED FOR CLARIFICATION OF ALT AND APCH CLRNC BEFORE LEAVING 3500 FT.