From what I can find, C is the end of year goal for kindergarten/beginning of year goal for first grade, and H is late first grade level. Since he is a beginning kindergartner, C is a year ahead, and H is almost two years ahead. (Some districts may have slightly higher or lower goals.) A few possible interpretations:
1. C = independent level, H = instructional level
2. C = current level, H = end of year goal level
If 1 is the correct interpretation, then the C level books coming home would be because they are supposed to be for leisure reading and fluency practice, which is generally supposed to be at the independent level, and not the instructional level.
If 2 is the correct interpretation, then the C level books are coming home because that is what they assessed as his instructional level, and H is the "reach" or goal level that he is expected to attain some months down the line.
More practically, it may be that C level books are coming home because they are the most challenging books available in a kindergarten classroom.
