ABCs ... no ... 123s

I just read a local story about schools in Jackson County changing the grading system - in essence, doing away with A,B,C, & F and replacing it with a more rubric-like 1, 2, 3, & 4.  The numbers are meant to indicate to parents how much a student has mastered a particular state standard.  So, instead of getting an A in reading, a child might get a 4 in "reads 65 words in a minute".  Basically, they are given a grade for each standard.  The idea is to give parents more information about the child's progress in each standard ... but I also have to wonder if it is a way to keep a record of the teacher's progress in teaching each standard?  The article only mentions that it will be implemented in elementary schools.  Could such a grading system work in middle or high schools?  I see a lot of good things about it, in particular the communication of mastery in specific concepts, rather than one grade for an entire subject.  This could help a child (and his parents) to see exactly where he needs to improve.  It could also show the child where he excels in that subject (or at least where he's doing okay) which could temper negative self-efficacy for the entire subject.  But there are also some aspects about this system that I am skeptical of, mainly because there isn't enough information in the article about how the schools will implement it, whether it will be for every subject or just standard-driven ones or if a student will have to get a certain number of 4s to pass the grade, or just how many of these specific grades the teacher will be required to send home each grading period.  Nevertheless, I have a feeling that this will catch on in Georgia and I think both I, and my students, need to begin looking into it and consider how it will affect their teaching.