An excellent overview for the most part, but I would take issue with one of your points.
Quote:
Without any sizable hoards however, the 1943-S sixpence is incredibly difficult to find in such a state. As a result, dealers tend to call examples of this date with slight wear, numerous surface marks, and impaired lustre as uncirculated. This process is known as market grading, in which the coin is awarded an uncirculated grading because such as coin is worth an uncirculated price.
PCGS on the other hand grade all coins to the same standards. For this reason, the 1943-S sixpence is much more valuable in an MS slab than it is graded locally as uncirculated while decimal coins will often be awarded MS gradings when they'd only be considered EF to an Australian dealer.
But PCGS
is a market grader. In the name of "eye appeal", they do grade different coins differently, over and above their "technical grade", depending on the perceived market value of the coin. Although PCGS founder David Hall is
on the record as disliking the term for semantic reasons, they say
right here on their glossary page that market grading is what they actually do.
If PCGS don't employ market grading for Australian coins, it's simply because they're not familiar enough with the Australian market to do it properly. But it is certainly employed in the various American coinage series which they grade.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis