HDFC
Pre closure penalty

I have an existing home loan with HDFC for last 2 years. They had offered me a scheme where for the first two years, the interest rate will be 8.5% and from third year onwards, it would be floating. recently, I had an offer from a different bank where the interest rate is going to be lesser compare to HDFC. So I decided to switch to the other bank. But HDFC is charging me 2% interest tax. I read somewhere that NHB has directed that for floating intrest, there should not be any penalty. But HDFC bank is chargning me penalty even if my interest is going to be loating from 3rd year onwards. What are the NHB policies for this dual interest kind of plans.