I am not sure about the part where 80% signalling needs to happen out of the last 144 blocks. For BIP91 to lock in 80% of 336 = 269 blocks need to signal before August 1st, 2017. As of now, 141 blocks are signalling. Here's hoping we reach the figure of 269 in the next two days. That delays fears of a chain split for another couple of months.