FLC ALLEGES ALTIMETRY IN ACFT WAS FAULTY.

Narrative

ON DSCNT INTO FRESNO WE WERE GIVEN A DSCNT TO 11000 FT. ATC GAVE US AN ALTIMETER SETTING OF 29.80. WE ALSO GOT AN ALTIMETER SETTING FROM OUR COMPANY (WHICH FROM PAST EXPERIENCE HAS BEEN MORE CURRENT) OF 29.87. NORMALLY AT AROUND THE 10000 FT ALT WE SET THE #1 AND #3 ALTIMETERS TO QFE. (AT FRESNO A CONVERSION OF .36). WE USED THE COMPANY ALTIMETER SETTING FOR THE CENTER ALTIMETER AND I WAS RESETTING MY #1 ALTIMETER TO QFE DURING THE LEVEL OFF AT 11000 FT. THE FO OBSERVED ME PASSING 10900 AND CALLED 11000 FT (A NORMAL EVERYDAY REQUIRED CALL). I GOT THE CLUE TO LEVEL AT 11000 FT AND BEGAN A CLB FROM AN ALT OF 10850 FT. AT THAT MOMENT ATC TOLD US THAT THEY OBSERVED US AT 10600 FT AND ADVISED US THAT WE WERE TO MAINTAIN 11000 FT. UPON LNDG IN FRESNO WE CHKED OUT ALL 3 ALTIMETERS; AND WITH THE CURRENT SETTING ALL 3 ALTIMETERS WERE OVER 100 FT OFF. THEY WERE NOT IN ERROR LEAVING DFW SO WE DOUBLECHKED THE ALTIMETER IN FRESNO WITH THE SAME RESULTS. THE PRESSURE WAS FALLING FAIRLY RAPIDLY AND THE SETTING SEEMED TO BE CATCHING UP WITH WHAT WE THOUGHT IT SHOULD BE. ON RETURN TO DFW ALTIMETERS CHKED OUT OK. I THINK 3 THINGS CONTRIBUTED TO THIS HAPPENING. 1) LESSON LEARNED -- DO NOT ACCOMPLISH ANOTHER TASK DURING LEVEL OFF. 2) BE WARY OF COMPANY ALTIMETER SETTING. WE GOT THE SETTING FROM ATIS WHICH WAS NOT CURRENT. 3) THERE WAS SOMETHING WRONG WITH THE SETTINGS OR EQUIP IN THE FRESNO AREA SINCE ALL 3 ALTIMETERS CHKED OK ELSEWHERE. ALL 3 COMPOUNDED THE SITUATION.