Regarding DrillDown/Drill Up in sap vc

Hi,

          I have created Hierarchy SAP VC Model, In this I have Wrote DrillDown/Drill Up Functions.Drill Up Function is Working Fine ,but Drill down is not Working properly.i have Mention below My  Formulas, Check it.

*Drill Down:*  'FILTER_NODE_IOBJNM=0HIER_NODE; FILTER_VALUE='&#ID[ACCELUL]@costelement_key&';FILTER_COLLAPSE=     ;FILTER_IOBJNM=Z0CSTELMT;CMD_1=CMD%3DDRILL_TO_LEVEL%26LEVEL%3D0%26IOBJNM%3DZ0CSTELMT%26DATA_PROVIDER%3DDP;R%3DDP;'

Drill UP:  'CMD_1=CMD%3DDRILL_TO_LEVEL%26LEVEL%3D'&NSTR(@costelement_node_level,'B')&'%26IOBJNM%3DZ0CSTELMT%26DATA_PROVIDER%3DDP;'

Regards,

devi