MLG FLC HAS SOME CONFUSION REF ALT CLRNC. ALTDEV IN HOLDING.

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WE WERE DSNDING IN HOLDING TO FL220; FO WAS THE PF. THE CAPT (PNF) WAS CLRING A SINUS BLOCK. I WAS CLRED LOWER; I THOUGHT IT WAS TO FL190. THE PNF DID NOT HEAR THE CLRNC; BUT SAW ME SET FL190 IN THE ALT REMINDER AND HE READ BACK THE CLRNC TO FL190. WHILE TURNING TO THE OUTBOUND HOLDING LEG; I NOTICED ANOTHER TARGET 8 MI AWAY AND AT OUR ALT ON THE TCASII (FL190). THE PNF IMMEDIATELY CALLED ATC TO ASK ABOUT THE TARGET. I ACQUIRED THE TARGET VISUALLY BY THE TIME ATC RESPONDED. THERE WAS NO CONFLICT; AS THE OTHER ACFT DID NOT GET CLOSER THAN 5 MI AND WAS ON THE INBOUND LEG. ATC THEN RESPONDED THAT WE WERE ONLY CLRED TO FL200 AND TURNED US INBOUND BEHIND THE TFC WITHOUT INCIDENT. AT THIS TIME I AM UNSURE AS TO WHETHER WE WERE CLRED TO FL190 OR FL200. I MAY HAVE SET FL200 IN THE ALT REMINDER AND IT BUMPED TO FL190 (IF IT IS HALF WAY BTWN SETTINGS; IT CAN READ WHAT YOU WANTED SET AND A MOMENT LATER; CLICK TO THE NEXT SETTING); OR ELSE WE WERE CLRED TO FL190 AND I SET IT PROPERLY. REGARDLESS OF WHAT THE CLRNC WAS; THE TCASII DISPLAY BROUGHT THE PROB TO OUR ATTN FIRST. THE TCASII HAS PROVEN ITS VALUE ONCE AGAIN. THERE WERE NO WARNINGS OR RA'S GIVEN BY THE TCASII AS THERE WAS NOT A CONFLICT. A CONTRIBUTING FACTOR WAS AN EAR BLOCK DEVELOPED BY THE CAPT DURING THIS LEG. IT MADE IT DIFFICULT FOR HIM TO HEAR AND REPEATEDLY DISTRACTED HIM AS HE TRIED TO CLR IT. THE PROB WAS SIGNIFICANT ENOUGH FOR THE CAPT TO REMOVE HIMSELF FROM THE REST OF THE TRIP AND TO RPT IN SICK.