Interest rate under section 372a

Dear All,

I have a query about the rate of interest applicable to the following contract considering the provisions of section 372A(3)

A valid by A Ltd to B Ltd for an advance was made by the company in the May 2011 under section 372A and the contract specifies the rate of interest being the 6% then effective bank rate and now RBI has increased to 9.5% then will this change effeect the cntracts already entred into and will they be liable to pay interest at the revised rates or at the rate of 6 % as per their contract

Please Specify

Waiting for an early and educative reply