FLC ATC MISCOM ON ALT CLRNC. NUMBERS MIXED BTWN HDGS AND ALTS. HDGS WENT FROM 200 TO 210 DEGS AND ALTS WERE 200 AND FLC THOUGHT 210.

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CLBING THROUGH 8000 FT TO 14000 FT; ATL APCH TOLD TO SWITCH TO ZTL ON 134.45. I CHKED IN WITH CTR 'XX 8500 FT CLBING TO 14000 FT REQUEST 210 DEG HDG FOR WX.' CTR RESPONDED 'XX CLB TO FL210 AND 210 DEG HDG APPROVED.' DURING XMISSION; PF ASKED ME TO REQUEST 200 DEG HDG. I RESPONDED BACK TO ZTL 'FL210 AND MAKE THAT A 200 DEG HDG FOR WX; XX.' CTR ASKED WHO WAS ASKING FOR 200 DEG HDG? AND I XMITTED 'XX WOULD LIKE 200 DEG HDG FOR WX.' CTR RESPONDED 'APPROVED AS REQUESTED AND EXPEDITE THROUGH 14000 FT FOR TFC.' I ACKNOWLEDGED. I THEN SET THE ALT ALERTER FOR FL210 AND CONFIRMED WITH PF. CLBING THROUGH 11500 FT CAPT INITIATED THE CLB CHK AND ASKED ME TO BRIEF THE PAX. WHILE BRIEFING THE PAX; ZTL ASKED US TO SWITCH TO ZTL ON 120.45. THE PF RESPONDED TO THE REQUEST. THE PF CHKED IN WITH ZTL AS 'XX CLBING TO FL210; 200 DEG HDG.' ZTL ACKNOWLEDGED. AFTER COMPLETING THE PAX BRIEFING; I CHKED BACK WITH THE PF WHO TOLD ME THAT HE HAD SWITCHED TO 120.45 AND CHKED ON CLBING TO FL210 AND THAT THE CLB CHK WAS COMPLETE. AT 20400 FT; 25 MI N OF CSG; CTR ASKED US TO DSND TO FL200 DUE TO ONCOMING TFC AT FL210. THE PF IMMEDIATELY DISENGAGED AUTOPLT AND BEGAN DSCNT FROM 20400 FT TO FL200. ACCORDING TO TCASII; THE OTHER ACFT PASSED ABOVE AND TO OUR L ABOUT 4 MI PLUS. CTR ASKED US ABOUT OUR ALT ASSIGNMENT AND WE STATED IT WAS FL210 AND THAT WE CHKED ON WITH HIM CLBING TO FL210. HE ACKNOWLEDGED AND TOLD US THAT THERE WAS A GENERATED ENCROACHMENT AND TO CALL CTR TO RESOLVE THE PROB.