BAPI_MATERIAL_AVAILABILITY ATP value is different from CO09 tcode

hi experts,

I am using bapi_material_availability for given plant/material/unit/batch and FM is returning values in table WMDVEX as below..

FUNCTION bapi_material_availability.

*"----------------------------------------------------------------------

*"*"Global Interface:

*"  IMPORTING

*"     VALUE(PLANT) LIKE  BAPIMATVP-WERKS

*"     VALUE(MATERIAL) LIKE  BAPIMATVP-MATNR

*"     VALUE(UNIT) LIKE  BAPIADMM-UNIT

*"     VALUE(BATCH) LIKE  BAPICM61V-CHARG OPTIONAL

*"  EXPORTING

*"     VALUE(AV_QTY_PLT) LIKE  BAPICM61V-WKBST

*"  TABLES

*"      WMDVSX STRUCTURE  BAPIWMDVS

*"      WMDVEX STRUCTURE  BAPIWMDVE

output:

BDCNT REQ_DATE   REQ_QTY            COM_DATE   COM_QTY        

00000 12.04.2014 9,999,999,999.000  06.03.2009             396.00

but some materials it is showing ATP STOCK value more than the UN-Restricted stock.

please suggest...