ALT DEVIATION--WRONG ALTIMETER SETTING.

Narrative

ACFT WAS CLRED IFR DAL TO BDL. ALTIMETER SETTING AT DEP WAS 30.32. ACFT CLRED FOR THE DAL 6 DEP TO GREENWOOD; MISS. TKOF WAS AT XA47Z (47L). AFTER TKOF ACFT WAS CLRED TO AN EASTERLY HDG AND WE IN TURN MADE SEVERAL INTERMEDIATE LEVEL OFFS--5000'; 11000'; 13000'; ETC. ACFT ULTIMATELY WAS CLRED TO FL290. BECAUSE WE HAD BEEN CLRED TO BDL ON A ROUTE DIFFERENT THAN PLANNED; THE ROUTE WAS REVIEWED PRIOR TO TKOF. HOWEVER; SOMETIME DURING CLBOUT; IN AN ATTEMPT TO REALIGN OUR COCKPIT PAPERWORK TO REFLECT THE NEW ROUTING; OUR FULL ATTN WAS SOMEHOW DIVERTED. THE AFTER TKOF AND CLB CHKLIST; A 10000' CHK AND 18000' CHK WERE ACCOMPLISHED WITH 1 NOTABLE EXCEPTION. NEITHER PLT SET THEIR RESPECTIVE ALTIMETERS NOR THE BACK UP TO 29.92 PASSING THROUGH FL180. CENTER ADVISED WE WOULD HAVE TO REMAIN AT FL290 FOR A PERIOD DUE TO XING TFC AT; I RECALL; FL310. ACFT WAS LEVELED OFF AT FL290 FOR A SHORT PERIOD WHEN WE AGAIN REQUESTED CLRNC TO CLB TO OUR FILED ALT FL330. REQUEST WAS MADE TO FTW CENTER. WE WERE ADVISED TO CHANGE FREQ TO; I BELIEVE; EITHER ANOTHER FTW CENTER CTLR OR MEM ATC. CENTER DID CLR US TO FL330 AND REQUESTED TO KNOW WHY WE HAD LEVELED OFF 400' BELOW FL290. IT WAS AT THIS TIME I REALIZED FAILURE TO RESET OUR ALTIMETERS WAS THE CAUSE OF OUR INACCURATE LEVEL OFF. ALTIMETERS WERE RESET TO 29.92 CLB TO FL330 WAS ACCOMPLISHED AD FLT CONTINUED W/O FURTHER INCIDENT.