Hi Sarvjeet,
As per the provisions of the act it is quite clear that advance FBT to be paid after considering your annual projected liability, so if u pay the advance FBT based on ur actual expenditure of a particular quarter and later on there is a huge expenditure which attracts the FBT Provisions then u have to pay the Interest if u fail to maintain the minimum %age of Advance FBT payment of ur total FBT Liability.
The Provision for Advance Payment of FBT is same that what we follow for the Advance Income tax. (Refered Section 208, 234A,234B,234C of IT Act to have a brief Idea, as the FBT Provisions are in line with this sections).