A B737 IS LOADED OVER WT WITH 2188 LBS OF FREIGHT THAT WAS NOT LISTED ON THE MANIFEST. ALSO; THE CAPT HAS CONCERN THAT A SLAT LED LIGHT DEFERRAL REQUIRES THAT THE ENTIRE INDICATING SYS BE DEFERRED.

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OPS AGENT TOLD US THAT IT WAS GOING TO BE TIGHT ON WT WHILE WE WERE WAITING IN THE JETWAY. WE RECEIVED A LOAD SHEET THAT WAS VERY CLOSE TO OUR MAX ATOG (116.7; OBS02 LIMITED). THE ACFT HAD MEL 27-4 WHICH DEFERRED BOTH LED INDICATION SYS. ON TKOF; WE RECEIVED AN LED ORANGE LIGHT (AS PREVIOUSLY WRITTEN UP) ON #5 SLAT. IT WENT AWAY AS WE LEVELED FOR FLAP CLEAN-UP. I COULD SEE THAT THE SLAT WAS PARTIALLY RETRACTED. ON CLBOUT; WE RECEIVED AN ACARS MESSAGE THAT THEY HAD NOT ENTERED THE 2188 LBS OF FREIGHT IN THE AFT BIN. THIS PUT US OVER ATOG FOR TKOF BY ABOUT 2000 LBS. WE DID NOT MAKE THE MISTAKE; THE LOAD SHEET DID NOT REFLECT THE FREIGHT THAT THE OPS AGENT APPARENTLY THOUGHT WAS NOT LOADED; BUT WAS. I DID THE CALCULATION FOR OUR NEW WT; WE LANDED EXACTLY AT LNDG WT SO EVERYTHING WORKED OUT. THIS COULD HAVE BEEN ONE OF THOSE TRAGEDIES OF CASCADING MISTAKES. THE ACFT HAD A DEFERRED INDICATION SYS; WHEN REALLY THE LED DEVICE WAS A PROB. THE MEL REQUIRES PART OF THE STALL SYS TO BE DEACTIVATED (CIRCUIT BREAKER COLLARED). WE TOOK OFF WITH AN INOP LED DEVICE; A PARTIALLY DEACTIVATED STALL WARNING SYS; WITH V-SPDS REFLECTING THE WRONG WT AND OVER GROSS BY 2000 LBS. THANKS TO MR BOEING; IT ALL WORKED OUT; BUT -- STRONG LETTER TO FOLLOW. THE INDICATION SYS SHOULD NOT HAVE BEEN DEFERRED; THE PROB WAS THE LED. YOU CANNOT DEFER AN LED; SO MAINT DEFERS THE INDICATING SYS. I WILL WRITE MORE ON THE IMPROPER MEL ON MY NEXT ASAP; BUT 27-4 IS ALMOST UNIVERSALLY USED INCORRECTLY -- MAINT DEFERS THE INDICATION SYS WHEN IT SHOWS AN LED PROB; WITHOUT CONSIDERING THAT; HEY; THERE REALLY IS A PROB.