A CPR LJ31 FLC DEPARTING ATL FAILED TO LEVEL OFF AT THE ASSIGNED ALT.

Narrative

A NORMAL CLRNC BEFORE ENG START STATED TO FLY ATL 4 DEP MAINTAIN 14000 FT. IT WAS READ BACK BY CAPT WITH NO ATC OBJECTION. THE PNF QUESTIONED THE 14000 FT DURING TAXI OUT TO RWY; BECAUSE THE DEP PLATE SHOWS 10000 FT. I ASSURED HIM THE READBACK WENT SUCCESSFULLY. AFTER CHKING IN WITH DEP CTL; THE PNF STATED THE CLB TO ALT WITH NO OBJECTIONS. THE CTLR WHO ROGERED OUR CLB TO 14000 FT THEN CALLED US WHEN WE WERE PASSING THROUGH 10400 FT; ACTING AS IF WE WERE CLRED TO 10000 FT. WE STATED WHAT WE KNEW AS FACT; STARTED DOWN TO 10000 FT FROM ABOUT 10700 FT; GOT RECLRED TO 14000 FT; AND WERE GIVEN A 30 DEG VECTOR TOWARDS OUR ON COURSE HDG. ATC FAILED ON 2 HEARBACKS IF THEY WANTED US AT 10000 FT. PLTS GAVE THEM AMPLE OPPORTUNITY TO ENSURE SAFETY. THEIR PERFUNCTORY ATTITUDE IS TO BLAME ON MOST OF THE INCIDENT. THE FLC COMPLACENCY FOR NOT QUESTIONING THE AMBIGUOUS CLRNC WHILE TAXIING OUT WAS THE OTHER PART OF THE BLAME. THE LESSON IS FOR ATC TO LISTEN TO READBACKS AND PLTS TO QUESTION ATC ON CLRNCS THAT CONFLICT WITH PUBS.