ACR LEAVES ASSIGNED ALT IN FOREIGN OP WHEN CALL SIGN IS USED IN ERROR OR CLRNC WAS MISUNDERSTOOD.

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WE WERE DSNDING FOR ARR AT FCO (ROME; ITALY). WE HAD BEEN CLRED DOWN FROM FL350 TO FL270 AND WERE EXPECTING FURTHER DSCNT. AS WE PASSED CORSICA WE RECEIVED AND ACKNOWLEDGED A CLRNC TO FL170 WHICH WE BELIEVED WAS FOR US. AS WE WERE DSNDING THROUGH FL185 THE ITALIAN CTLR ASKED FOR OUR ALT. HE THEN STATED THAT WE SHOULD STILL BE AT FL270 AND REQUESTED US TO MAINTAIN FL190; WHICH WE IMMEDIATELY COMPLIED WITH. WE HAD BEEN IN DSCNT FOR AT LEAST 4 MINS BEFORE ATC NOTICED OUR DEV. 2 PLTS HEARD AND AGREED ON THE CLRNC TO FL170. TO SAY WE WERE SURPRISED IS AN UNDERSTATEMENT. NO CONFLICT IN TFC WAS OBSERVED ON THE TCASII DURING THE EVENT. SOME ITALIAN CTLRS ARE PARTICULARLY HARD TO UNDERSTAND AS WAS THE CASE HERE AND OBVIOUSLY CONTRIBUTED TO THE MISCOM. WE OFTEN ASK FOR CLRNCS TO BE REPEATED TO VERIFY ROUTINGS ETC; IN EUROPE. IN THIS CASE WE WERE EXPECTING A DSCNT AND THE CLRNC WAS HEARD AND AGREED UPON BY 2 PLTS AS WAS THE CALL SIGN ACR X; BUT WAS EITHER GIVEN IN ERROR OR MISINTERP. WE CONTINUED TO ROME WITHOUT INCIDENT. WE ALL KNOW WE MUST LISTEN VERY CAREFULLY IN A FOREIGN ENVIRONMENT; BUT SOMETIMES ANTICIPATING A CLRNC CALLS FOR EVEN GREATER VIGILANCE BECAUSE OF THE CLRNC YOU DON'T SET.