GOV Y CLB THROUGH ASSIGNED ALT HAD LTSS FROM ACR X TCASII TA RA EVASIVE ACTION TAKEN DSND. PLTDEV.

Narrative

ACR X WAS AT FL260. I CLBED GOV Y TO FL250. I WAS WORKING PAXTO HI SECTOR; ZFW; AT AN EXTREMELY BUSY TIME. ACR X CALLED TO SAY HE WAS TAKING A TCASII RESOLUTION AND DSNDING. I LOOKED AT Y'S FULL DATA BLOCK AND SAW THE RPTED ALT OF FL254. I IMMEDIATELY STATED TO Y THAT HIS ASSIGNED ALT WAS FL250. Y SAID; 'ROGER; I AM LEVELING AT FL250.' I TOLD ACR X TO RETURN TO FL260; THAT THE Y WAS AT FL250. OBVIOUSLY; THESE ACFT WERE CONVERGING. HAD ACR X NOT HAD TCASII; THE INCIDENT STILL MAY HAVE HAPPENED. THE UNKNOWN IN THIS CASE IS WHETHER THE Y WOULD HAVE STOPPED AT FL250 HAD I NOT SAID ANYTHING. MY FEELING IS THAT THE Y PROBABLY SAW THE ACR; REALIZED HE HAD OVERSHOT HIS ALT AND GOT BACK TO FL250 IN THE QUICKEST WAY POSSIBLE. WITH OUR COMPUTER WE ONLY GET UPDATES EVERY 10 SECONDS; SO WHEN I SAW FL254 ON THE Y; HE HAD PROBABLY ALREADY STARTED BACK TO FL250. BECAUSE ACFT CAN ARBITRARILY LEAVE THEIR ASSIGNED ALTS IN PCA; I DON'T LIKE TCASII USED IN CTRS. IT WAS VERY DISTURBING; DISORIENTING; AND DISRUPTIVE TO MY ATC PERFORMANCE TO HAVE THIS HAPPEN. I RECOMMEND NO TCASII IN PCA. SUPPLEMENTAL INFO FROM ACN 232160: ACR X AT FL260; PROCEEDING DIRECT TO SCY VOR; TCASII TA RECEIVED. ACFT APCHING AND CLBING FROM 1:30 POS. TCASII RA COMMANDED DSCNT AND GOV Y ACFT SPOTTED VISUALLY. STARTED DSCNT AND ADVISED ZFW. AT FL257 GOV Y OBSERVED DSNDING AS TCASII COMMANDED A CLB. KEPT GOV Y VISUAL AND CLBED BACK TO FL260.