There are two views about how to Kasher in the method of כבולעו כך פולטו - the way the non Kosher goes in is the way it comes out.
One is to require only slightly above the temperature of the non-Kosher. The other is to require, in the case of hot water, full boiling (212 degrees Fahrenheit) and not relying on any assumptions about the temperature.
The former option is quoted here by the CRC on footnote 28. The latter opinion (which the CRC article alludes to a "custom" to try to satisfy) I have often heard the Shulchan Aruch HaRav quoted as a source for the opinion, but I haven't seen it inside.
The notation on the cheese is to indicate that the Kashering is done to this stricter standard. I remember 20 years or so ago there was a wide variety in Kosherization practices with regards to this. Manufacturing companies prefer the lower temperature because it puts less stress on their equipment, and the lower demand for Kosher foods then meant that more certifying agencies went along with it.
Today Kashering with boiling water at 212 is much more prevalent, but some companies (like apparently Anderson Cheese) like to advertise it more prominently.
Although when it comes to milk a statement about Kashering at 212 will be in regards to "Cholov Stam" issues, when it comes to cheese, the issue is non-Kosher cheese (Gevinas Akum) not just whether or not it was Cholov Yisroel. In order to make something not Gevinas Akum it requires supervision at the time of rennet insertion, so this is highly unlikely to have been what preceded the Anderson production.