NMAC BTWN A BEECH BONANZA BE36 DSNDING AT NIGHT ON THE ILS AND PROP TWIN PASSING OVERHEAD; ALSO DSNDING ON THE ILS. APCH CTLR HAD JUST TURNED RPTR OFF LOC FOR SEPARATION FROM THE OVERTAKING; FASTER TWIN; IN ACCORDANCE WITH WHAT HE HAD SAID HE WOULD BE DOING.

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I WAS ON LYNX7 STAR TO VNY. CTLR (I THOUGHT) CLRED ME FOR RWY 16R ILS APCH. HE LATER CLAIMED HE TOLD ME TO MAINTAIN 5000 FT. I DO RECALL HE TOLD ME HE WOULD BE ALLOWING FASTER TFC TO PASS ME AND WOULD BE TURNING ME OFF LOC LATER ON. I THEN HEARD AN EXCHANGE BTWN A GULFSTREAM AND MY CTLR. GULFSTREAM WAS CLRED FOR VISUAL; VNY; BUT GULFSTREAM CORRECTED CTLR AND SAID 'NO; GOING TO BUR.' CTLR SAID OK AND I THOUGHT THAT WAS THE FASTER TFC; SO I CONTINUED APCH FIGURING I WOULD CONTINUE ON THE APCH. CTLR ASKED GULFSTREAM WHERE HE WAS GOING. GULFSTREAM SAID BUR VISUAL VIA NEWHALL PASS (WHICH IS WHERE I WAS). CTLR REBUKED GULFSTREAM AND SAID 'NEGATIVE; YOU ARE CLRED VISUAL BUR; YOU GO DIRECT; THIS ISN'T A CONTACT APCH; DO YOU UNDERSTAND SIR?' GULFSTREAM REPLIES 'YEA.' THEN CTLR ASKS ME; 'SAY ALT.' I SAY; '4500-4600 FT ON ILS.' HE SAYS; 'I TOLD YOU TO REMAIN AT 5000 FT; I TOLD YOU FASTER TFC BEHIND. TURN R (NO HEADING GIVEN) AND CLB IMMEDIATELY.' I COMPLY AND AS I START R TURN OUT OF 4500-4600 FT TWIN PROP GOES OVERHEAD TO ARPT (VNY) SAME DIRECTION AS ME AT ABOUT 5000 FT. WHAT IF I HAD STAYED AT 5000 FT AS HE SAID HE WANTED? I WAS ONLY DOING ABOUT 110 KTS AND MAYBE 130-140 KTS FOR TWIN. APCH SHOULD HAVE DESCRIBED FASTER TFC AS PROP TWIN AND I WOULDN'T HAVE ASSUMED IT WAS THE GULFSTREAM. I SIMPLY DON'T RECALL BEING TOLD TO MAINTAIN 5000 FT AND WHAT IF I DID?