Ppf query

Hi I opened a PPF account in 2000 which as per law matured in 2015 after 15 years. My query is regarding PPF and is as follows: Now in FY 2015-16 the account is matured and there is an option to withdraw the entire or part of the amount or pay a minimum Rs 500 to lock it for another 5 years. However I made no contribution in 2015-16 as I was planning to buy a house and needed the entire sum.But due to certain reasons I may not need to withdraw the money as of now.As it may materilize in 2016-17 I plan not to make any contribution in 2016-17 to my PPF account so as to keep the funds handy as if I make a contribution 40% would be again locked for 5 years. Hence as per PPF rule if I do not make a contribution 1 year after maturity the same is considered to be a PPF account without contribution. Now if I decide to continue my PPF account by paying an X amount in 2017-18 will the PPF accept the same as with contribution considering that I made no contribution post maturity for 2 years. If so will there be a penalty and to what extent. Please clarify.