Dear Prasad,
In Brazil we don´t have any special setup for WHT to make the standard SAP different from other countries, just the setup to assign the WHT with the Nota Fiscal condition type.
Please check your WHT Tax Type and Code setup:
In the tax type you will check how the base amount is calculated while in the code you should set the percentage as 100% and define the WHT rate as:
Best regards,
Gabriel Coleti