RPTR CLRED ACFT X FOR A TOUCH-AND-GO ON RWY 13. BECAME DISTR WITH TABULATING HRLY TFC COUNT AND FORGOT ABOUT ACFT X. RPTR THEN CLRED ACFT Y FOR TKOF ON RWY 17. ACFT X HAD TO TAKE EVASIVE ACTION TO MISS ACFT Y.

Narrative

I WAS WORKING THE LCL CTL POS WITH 2 CONVERGING RWYS IN USE (RWY 17 AND RWY 13). THERE WERE 3 ACFT IN THE TFC PATTERN TO RWY 17 MAKING PRACTICE TOUCH-AND-GOES. ALL HAD EACH OTHER IN SIGHT AND WERE DOING A GOOD JOB OF FOLLOWING EACH OTHER. ACFT #1 CALLED ABOUT 12 MI OUT ON A PRACTICE ILS APCH WITH GEAR. I ASSIGNED CLBOUT INSTRUCTIONS (RWY HDG MAINTAIN 3000 FT) AND CLRED THE ACFT FOR A TOUCH-AND-GO ON RWY 13. I RESUMED MY SCAN OF RWY 17; AND ALSO BEGAN TO TRY AND COUNT THE TWR'S LAST HR OF AIR TFC ACTIVITY. DURING THIS TIME ACFT #2 CALLED READY FOR DEP ON RWY 17. I WAS ASKING ANOTHER CTLR FOR THEIR HELP IN CORRECTLY COUNTING THE TFC WHEN I CLRED THE SECOND ACFT FOR TKOF. ONCE AIRBORNE; I NOTICED WHAT APPEARED TO BE A DOUBLE XPONDER TARGET ON THE #2 ACFT. AT THAT TIME; ACFT #1 STATED 'TWR WE ARE DEVIATING FOR TFC.' BOTH ACFT WERE ON CONVERGING COURSES TOWARD THE APEX OF THE 2 RWYS. I HAD FAILED TO REMEMBER THE ACFT TO RWY 13. I BELIEVE THIS TO BE CONTRIBUTED TO THE NEW TFC COUNT PROC; WHICH CAUSED ME TO DIVERT MY ATTN AWAY FROM THE TFC SIT. I BELIEVE ATC SHOULD NOT BE RESPONSIBLE FOR COUNTING THE AIR TFC ACTIVITY WHILE ACTIVELY CTLING AIR TFC.