The 17 minutes is based mostly on the time when the difficulty was 46. Now it's down to 11, so naturally the blocks are being solved faster. The time per block is a rolling average, so the calculation takes a while to catch up.
On nyanmine there is an error and it says the network hash has dropped down to 40-50Mh/s, that's why it's saying the next diff change is 0.6-0.7 and that each block is going to average 15-17 minutes even at difficulty 11. This is a false report though, since the pool hashrate reported is greater than the network hashrate which is obviously impossible.
seems much faster 
