ACR X CLB THROUGH OCCUPIED ALT HAD LTSS FROM ACR Y. SYS ERROR.

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ACR X MD88 OFF CVG AT 330; REQUESTING 370. THE ACFT WAS LEVEL FOR SEVERAL MINS BEFORE THE PREVIOUS CTLR PUT X ON MY FREQ. I JUDGED BY HOW QUICKLY THE X GOT TO 330 AND BY THE PLT'S ESTIMATE OF HOW LONG IT WOULD TAKE TO REACH FL370 THAT THERE WOULD BE PLENTY OF TIME TO CLR FL350 ACR Y. THE CLBER WAS SEBOUND; AND THE FL350 Y WAS SWBOUND. I CLRED X TO FL370; AND WENT ON TO OTHER THINGS; THOUGH I PUT A POLYGON UP ON THE CLBER TO REMIND MYSELF TO COM BACK TO IT. BY THE TIME I GOT BACK TO IT (I WAS BUSY); IT WAS CLR THAT THE RATE OF CLB WAS TOO SLOW. ALSO; X HAD A SLIGHT L TURN IN HIS FLT PLAN AT HVQ; AND I THOUGHT HE WOULD BE GOING STRAIGHT. WHEN X MADE THE TURN; HE BECAME A CONFLICT WITH THE 350 ACFT. I TURNED BOTH 15 DEGS R AND THEN TO HARDER HDGS. THE 2 TURNS TO THE CLBER ADDED UP; TO ABOUT 55 DEGS AND TO THE FL350; ABOUT 45 DEGS. IT WAS A LITTLE TOO LATE AND I ASKED X TO VERIFY LEVEL AT 370. X SAID HE WAS OUT OF 367; AS I WAS ASKING AGAIN; AEDP ACTIVATED AND I LOST SEPARATION. HIS RPT CAME ABOUT 10 SECONDS TOO LATE.