Price protection means, no change in price until the expiry of current subscription only not for renewals...
Ex: If you start a annual pack at Rs.2000 on 1 June 2015... And then TS increase that pack price to Rs.2500 on Jan 2016... you need not pay the additional rs.500 until the expiry that is 31 May 2016... but on renewal you should pay the new price..