Hi Vijay,
First of all, can you explain the logic you want to implement? Please read: How To: Ask questions about Script Logic issues
Second - please read about default.lgf: How-To: Write default.lgf
And at the end - read help for TMVL: TMVL Parameter - SAP Business Planning and Consolidation, version for SAP NetWeaver - SAP Library
For multiple TIME members in TMVL
"The first period of the TIME_SET is used as the base period for a negative offset and the last period of the TIME_SET is used as the base period for a positive offset."
Vadim