These NOCs are kind of "Bhatta tools" and Sindh Police use them to perfection. I have never tried to get for any of my travel. Once I encountered a situation where Police stopped me. Though they ask for huge amount but eventually they settle for Rs. 100 - 200.
You can easily cross Ubaro within 11-12 hours with decent stops and if you don't stop much you can make it in even less time. I guess there is no point in worrying about this, just remember to leave early.