LESS THAN STANDARD SEPARATION WHEN ACR-MLG IS ALLOWED TO CLIMB THROUGH THE ALT OF CPR-SMT.

Narrative

SMT X LEVEL AT FL180 ON J80; 15 MI SW OF ETX VORTAC; PROCEEDING SWBOUND (GND SPD WAS ABOUT 200 KTS). SECTOR 11 CALLED FOR A POINTOUT OF MLG Y (32Q KTS G/S); LOCATED OVER THE PTW VORTAC NWBOUND ON THE PTW 320 DEG R TO INTERCEPT J64 AND PROCEED WBOUND. MLG Y WAS OUT OF 15000' FOR 17000'. SECTOR 11 REQUESTED CTL TO CLB TO FL260. I APPROVED THE POINTOUT W/O REFERENCING SMT X. I FELT THAT MLG Y WOULD GO BEHIND AND ABOVE SMT X. I BECAME INVOLVED WITH OTHER TFC IN ANOTHER PART OF MY SECTOR; NOT NOTICING THE VERY POOR CLB RATE AND INCREASE OF SPD ON MLG Y. THE C/A DID NOT GO OFF UNTIL THERE WAS 4.9 MI. THE ACFT (MLG Y) PASSED BEHIND SMT X WITH 4.4 MI LAT SEP AT 200' VERT SEP. NO CORRECTIVE OR EVASIVE ACTION WAS TAKEN; OR NECESSARY; SINCE THE ACFT HAD ALREADY PASSED AND WERE ON DIVERGING COURSES. I FEEL I COULD HAVE AVOIDED THE ENTIRE SITUATION OF JUST REFERENCING SMT X AND NOT ASSUMING (BAD WORD IN ATC!!!) MLG Y WOULD PASS BEHIND AND ABOVE SMT X. POSITIVE SEP MUST BE MAINTAINED AT ALL TIMES. I LEARNED ANOTHER VALUABLE LESSON FOR THIS SITUATION; SO AT LEAST SOME GOOD COMES OUT OF IT.