To all intents and purpose there are also plenty of 71s, 72s and possibly higher based on the Sheldon or any other scale. The minute you assign a number to anything it is supposed to represent a particular coin's qualities. The collector then looks at several similarly graded coins and decides which one is the better. This one or that one has less/more nicks, wear, bagmarks etc. All of the numbers assigned are a reflection of the mood of the grader(s) on that particular day. That a coin can be repeatedly submitted and be slabbed in wildly differing grades on each occasion is testament to the failings of the system, as any firmly grounded grading scale would not have the scope to assign a subjective grade. As a Sheldon 70 or CGS 100 is supposed to be perfection, it should not be impossible for any scale to have examples with the top grade, even though I've heard it said that CGS will never give a coin 100. There are many examples in MS70 meaning that all should be identical in terms of grading assessment. Any scale must have the parameters defined with individual grades having their own criteria. This is where subjectivity comes in, as, with the exception of perfect or totally flat coins, all are in an intermediate state of preservation which is contentious in absolute number grading. I quite agree with rpeddie's query about the missing 18 points, after all, an assessment should have been made and the results documented in order to lose them. I suspect that this would be deemed to be releasing trade secrets, as the TPGs purport to have knowledge over and above 'non-professionals'. Once their criteria are known, anyone could grade which is not good for their business models.