AN ACR DC10 FLC WAS TOLD BY THE APCH CTLR THAT THEY MADE THEIR TURN 10 NM EARLY WHILE INBOUND ON THE STAR. THE FLC CHKED THEIR SELECTED NAVAIDS AND ALL RAW DATA INDICATIONS WERE CORRECT. WINDS AT 12000 FT WERE 250 DEGS AT 80 KTS.

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FLT MSP TO SEA; ON GLASR ARR. WE INTERCEPTED THE SEA 020 DEG RADIAL (RAW DATA ON BOTH CAPT'S AND FO'S HSI). PROCEEDED TO HETHR INTXN (10 DME SEA) TURNED TO 160 DEG HDG AS PUBLISHED AT 12000 FT. AFTER OUR ROLLOUT ON 160 DEG HDG; SEA APCH INQUIRED OUR HDG; THEN ADVISED OUR TURN WAS 10 MI EARLY. WE SHOWED ON COURSE AS PUBLISHED ALL THE TIME. THE WIND AT 12000 FT WAS APPROX 250 DEGS AT 80 KTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAYS THAT HE IS CERTAIN THAT HE DID NOT TURN EARLY. THE DC10 FLC RECHKED THEIR NAVAIDS RIGHT AFTER THE TURN AND THE CTLR'S QUERY; AND THEY STILL INDICATED THAT THEY HAD NAVED CORRECTLY. THEY WERE ALSO USING INS. THE RPTR ALSO FEELS THAT THE EFFECT OF THE WINDS HAD TO HAVE NOTICEABLY AFFECTED ALL TFC THAT NIGHT; SO THE CTLR'S QUERY IS STILL UNEXPLAINABLE. SUPPLEMENTAL INFO FROM ACN 326684: CONTRIBUTING TO THE CONFUSION WAS FACT THAT WE HAD MISTAKENLY ENTERED A WRONG WAYPOINT IN INS UNITS FOR POINT AFTER HETHR INTXN. THIS DID NOT CAUSE THE DEV THOUGH; BECAUSE PF (FO) WAS NAVING IN VOR TRACK MODE AND USING VORTAC NAVAIDS TO FLY THE ARR. MAIN CONCERN OF APCH CTL SEEMED TO BE THAT THEY DID NOT CTL AIRSPACE THAT WE WERE FLYING INTO AND THERE WAS TFC THERE THAT POSED A POSSIBLE CONFLICT.