WHILE EXECUTING A STAR DURING MODERATE TFC CONDITIONS; AN HS25 WAS ISSUED ADDITIONAL STAR ALT XING CHANGES THAT WERE INCORRECTLY TRANSPOSED INTO THEIR VNAV FMS. ATC CHALLENGED THEIR ALT WHEN LEVEL; ISSUING A 90 DEG TURN FROM DSNDING CONFLICTING TFC. ATC APPARENTLY DID NOT CATCH FLC INCORRECT ALT READBACK.

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NORMAL OPS ON IFR FLT PDK DIRECT TEB. I HAD PROGRAMMED THE VNAV TO CROSS KERNO INTXN AT FL260 PER THE STAR. ATC THEN ISSUED A CLRNC TO CROSS SWANN INTXN AT FL260 (1 FIX EARLY). I REPROGRAMMED THE BOX FOR SWANN INTXN AT FL260. THE NEXT CLRNC WAS TO CROSS 15 NM S OF DQO VOR AT 11000 FT. BEFORE WE COULD QUESTION THE CLRNC HE CORRECTED HIMSELF TO MAKE THE XING RESTR AT YARDLY VOR. I PROGRAMMED THE VNAV AND THE FO SET THE ALT ALERT AND I VERIFIED THAT HE SET 11000 FT. WE HAD BEEN LEVEL AT 11000 FT FOR ABOUT 30 SECONDS WHEN ATC QUESTIONED OUR ALT. WE REAFFIRMED 11000 FT PER OUR CLRNC. AN IMMEDIATE 90 DEG L TURN WAS REQUESTED AND EXECUTED. WHILE IN THE TURN THE TFC WAS POINTED OUT AND SEEN. ATC GAVE US A PHONE NUMBER TO CALL. THE NUMBER WAS DIALED AND A SHORT DISCUSSION WAS HAD. THE FIRST PROB WAS THAT ATC ISSUED CLRNCS (XING RESTR) THAT WERE CONTRARY TO THE STAR. THIS INCREASED COCKPIT WORKLOAD. THIS FLT DEPT POLICY FOR ALT CHANGE IS THAT THE PNF RECEIVES THE CLRNC AND SETS THE ALT ALERTER. HE MUST RECEIVE ACKNOWLEDGMENT FROM THE PF BEFORE REMOVING HIS HAND FROM THE ALT ALERTER. BOTH PLTS ARE RATED WITH OVER 1000 HRS IN MAKE AND MODEL. THIS WAS VERY DISTURBING. IT WOULD BE NICE TO BE ABLE TO HEAR THE TAPE ESPECIALLY IF WE COULD LEARN THE HOW OR WHEN THE MISCOM OCCURRED.