"all I've noted were instances where, with news, the PPS has gone up or stays static, but in either case is followed by what I perceive to be rather vigorous bashing. And the PPS suffers - perhaps as a result of such bashing."

By this statement, you seem to have specific time frames and instances in mind where you have in fact observed this rather vigorous bashing and subseqent PPS fall. Can you please point out a couple of those instances? I'd like to go back and look at them. TIA.