A B717 PLT QUESTIONS WHETHER HE MISINTERPED AN APCH CLRNC BECAUSE HE WAS FATIGUED FROM A LONG DAY WITH POOR PREFLT REST.

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SCATTERED CLOUDS AT ABOUT 2000 FT BTWN US AND THE ARPT. ACFT AHEAD CALLED ARPT IN SIGHT AND WAS CLRED VISUAL. WE RPTED ACFT AHEAD IN SIGHT AND WERE CLRED VISUAL TO FOLLOW. SINCE ACFT AHEAD CALLED THE FIELD AND OTHERS WERE GETTING IN VISUALLY; I ASSUMED THAT THERE WAS A CLR SHOT AT THE ARPT BEHIND THE SCATTERED CLOUDS. FLEW AROUND CLOUDS AND WAS CONFRONTED WITH NO OPENING; BUT RATHER ANTHER CLOUD. COULD NOT DSND DUE TO CLRNC TO MAINTAIN 2500 FT UNTIL 6 DME TO KEEP US OVER TFC TO OTHER NEARBY ARPT. THOUGHT THAT BY THE TIME WE CLBED UP FOR RE-SEQUENCING WE WOULD BE CLR OF CLOUDS (WHICH TURNED OUT TO BE THE CASE); SO I CONTINUED AND POPPED OUT THE OTHER SIDE. WHILE THIS WAS GOING ON; AT ABUT 7 DME (5 MI FROM THE RWY); APCH TOLD US TO 'MAINTAIN 2000 FT UNTIL 4 MI.' IN THE PROCESS OF CLRING THE PREVIOUS ALT RESTR; RE-EMERGING FROM THE CLOUD AND MAKING OUR TURN TO THE ARPT; I DSNDED BELOW 2000 FT PRIOR TO 4 DME. I NOTED THIS TO THE FO; AND HE SAID; 'NO; WE'RE OK.' AFTERWARDS; HE SAID THAT HE HAD TAKEN THE CLRNC TO MEAN 4 MI FROM THE ARPT; SO WHEN HE SAW ME DSND BELOW 2000 FT; HE NOTED THAT WE WERE WITHIN 4 MI AND THOUGHT IT WAS OK. IN HINDSIGHT; I'M NOT SURE WHAT THE CLRNC MEANT; SINCE WE BOTH HAD A DIFFERENT UNDERSTANDING OF IT. ATC DID NOT MENTION ANYTHING ABOUT A POSSIBLE ALTDEV; SO PERHAPS THE FO'S INTERP OF THE CLRNC WAS CORRECT; OR PERHAPS WHATEVER OTHER ACFT THEY WERE CONCERNED ABOUT DID NOT GET CLOSE ENOUGH TO WARRANT ANY COMMENT FROM THEM. I SHOULD NOT HAVE ACCEPTED A CLRNC THAT WAS BASED ON THE ASSUMPTION THAT I WOULD BE ABLE TO VISUALLY NAV TO THE ARPT BECAUSE THE ACFT AHEAD OF ME SAID HE COULD. FROM THAT POINT; I WAS BEHIND THE AIRPLANE AND HAD LOADED MYSELF UP TO THE POINT THAT I WAS WILLING TO ACCEPT AN UNCLR CLRNC AND NOT QUESTION IT (ALTHOUGH IT DID COME RATHER LATE IN THE GAME; EVEN IF THINGS HAD BEEN GOING MORE ACCORDING TO PLAN). HUMAN FACTORS WOULD INVOLVE THE FACT THAT THIS WAS AT THE END OF A LONG DAY (OUR NINTH LNDG AND ABOUT 6 HRS OF FLYING). ALSO; I HAD A MEDIOCRE NIGHT'S SLEEP PREVIOUS TO THIS DAY. I DID NOT FEEL VERY FATIGUED; BUT IN HINDSIGHT THINK THAT THIS MAY HAVE BEEN A FACTOR IN MY APPARENT WILLINGNESS TO ACCEPT PERFORMANCE FROM MYSELF AND OTHERS THAT WAS LESS THAN WHAT I WOULD NORMALLY EXPECT OR ACCEPT.