please help...

first of the when the bank account number changes , any way u can tell change in account or opening or closing of bank account ..

so as far as u r question goes its important ,cumpolsury to provide the information in change of any account even the new account should be informed , the basic resons is in case of any default by the assess the dept. can cease the account , it useful even to cross check the sale and purchase tracation amount received and paid

the details of the bank account should be provided to the departement in the registration form itself , however if there is any changes it can be inform through the same form as rquired for the registration , its must to provide the information at the time of registration and any changes there after to dept.