MLG CREW HAD ARTCC RADAR CTLR MISSPEAK CLRNC.

Narrative

WHILE DSNDING ON THE NORWICH 2 ARR TO BOS; CTR CLRED ACR FLT ABC 'DIRECT PVD; CROSS AT 11000 FT AT 250 KTS.' JUST OVERHEAD THE PVD VOR AND STABILIZING AT 250 KTS; THE CTLR ISSUED A CLRNC TO 'TURN R HEADING 110 DEGS; DSCNT TO 8000 FT; SPD 280 KTS; SPACING INTO BOSTON.' I READ BACK THE CLRNC AND THE FO (FLYING AT THE TIME) INPUT 10000 FT ON THE MCP ALT WINDOW; HEADING 110 DEGS; AND INITIATED A VERT SPD MODE DSCNT AT APPROX 1000 FPM. I CLARIFIED 8000 FT ASSIGNED WHEN WE BOTH POINTED AT THE ALT WINDOW AND HE STATED THAT HE HEARD 10000 FT. AT THIS TIME THE CTLR WAS VERY BUSY WITH SEVERAL ACFT AND ISSUING MANY CLRNCS. AFTER A FEW SECONDS I HAD A BREAK IN THE COMS TO VERIFY THE ALT ASSIGNED AS 8000 FT. THE CTLR RESPONDED WITH 'YOU'RE ASSIGNED 11000 FT.' THE FO IMMEDIATELY RESET 11000 FT IN THE WINDOW AND SET A VERT SPD CLB BACK TO 11000 FT. AT THIS TIME I WAS ACKNOWLEDGING THE CLRNC AND CHKING THE TCASII DISPLAY FOR CONFLICTS (TCASII WAS IN 20 NM SCALE; SET TO LOOK 'BELOW'). NO TFC WAS OBSERVED WITHIN 8-10 NM AND NO TA OR RA SYMBOLS OR WARNINGS WERE OBSERVED. ANOTHER ACFT ON THE FREQ WAS HEARD TO ASK 'WHO SCREWED THIS UP; UP HERE?...' AS WE LEVELED OFF AT 11000 FT HEADING 110 DEGS THE FO AND I COMMENTED ON THE UNUSUAL METHOD OF SPEEDING UP FOR SPACING IN BOSTON. THEN THE CTLR ISSUED US A FREQ CHANGE AND THE VOICE SEEMED DIFFERENT; POSSIBLY ANOTHER CTLR TAKING OVER. DURING THE BRIEF DSCNT WE WENT FROM 11000 FT TO 10400 FT AND BACK TO 11000 FT. NO MENTION OF THE SIT WAS MADE TO US BY ANY ATC AGENCY AND NO LACK OF SEPARATION WAS OBSERVED. POSSIBLE CONTRIBUTING FACTORS: BUSY CTLR; HEADING 'SAME' AS ALT; IE; 110 DEGS AND 11000 FT; MULTIPLE ACFT ON FREQ.