Actually that's how the US is thinking about it, not Pakistan... They want to tie it to performance, and our simple reply to that would be "we don't care enough about the performance or the money". This money is not benefiting Pakistan. We lose money while fighting the war, and they reimburse us...
Just because we've removed forces from a small region doesn't mean that there's a significant dent in the 82,000 strong deployment that is done over there. We give them our bills thats it.
Actually US is not paying for our fight against local extremism. Just for the Taliban and their movement across the border. The issue of camps operating (at least if they are permanent camps and not moving from here n there like caravans) on the Afghan border is so lame. Pakistan on every occasion has said "Ok if you know where those camps are, why don't you tell it to us?" Not once has there been any answer to this question. Since its not the US government who ever says this on the record it's just some one or two person in the establishment voicing his opinion.