15h & TDS deduction

even after asubmitting 15h, bank deducts TDS for the reason total estimated income from that bank exceeds Rs 2.50 lacs;

As per RBI guidelines,

-1.  whether Bank need not deduct TDS, merely relying on the declaration in 15H by the client ?

or

-  2. Whether, Bank should deduct TDS if total extimated income from the bank exceeds certain amount?

-3.  if bank has to deduct TDS, what is the cut off Quantum of estimated total income from that bank?