The point is that he have to take what Johnson Matthey publishes with a huge grain of salt. AMPLATS was giving them a $89 million dollar discount and they are its largest customer. This explains why they have been so understating the troubles in SA. They don't want to run the price up and pay more and upset their biggest supplier to boot.
From what I've seen, Johnson Matthey is the most informative source you will find in PGM reporting. Everyone has some conflicts of interest. JM may have plenty, but some offset others. As a middle man, they sell in addition to buying, so also benefit from an increasing price. I wouldn't read to much into the Amplats deal with regard to JM credibility.