Hi Devang,
If you want to use 64 bit Excel for EPM Addin you need to install EPM Addin version for Large Volume Data Source.
See EPM installation guide : http://service.sap.com/~sapidb/011000358700001223362010E
3.2 Installation Prerequisites for EPM Add-in, .Net Framework 4.0 (Version for Large
Volume Data Sources and for Microsoft Office 64-bit)
If you want to install the EPM Add-in version for Large Volume Data Sources or for Microsoft Office
64-bit edition, you must ensure that the following prerequisites are installed, before running the setup
Also this link should help Best Practices For Reporting Against SAP Business Planning and Consolidation (Powered by SAP HANA), utilizing the EPM Add-in for Excel
Regards,
Ridwansyah