Common Core has expanded the Lexile levels in the standards, giving teachers who are required by administrators to use Lexiles more flexibility in their choice of books. The change was slipped into the fairly new publication, "Supplemental Information for Appendix A of the Common Core State Standards for English Language Arts and Literacy: New Research on Text Complexity" found at
At the very least, Common Core should be featuring this change on their home page so the word gets out about it. I only saw the changed levels because I came across a reference to the Supplement and went to take a look.
You'll find the expanded Lexiles on page 4 along with other reading formula levels
by grade band. The footnote explains that, "This change was provided
in response to feedback received since publication of the original scale
(published in terms of the Lexile® metric) in Appendix A."
No school should be using Lexile levels as the sole factor in choosing books. It is particularly disturbing to hear about middle school and high school ELA programs that have dropped novels that worked well, discarded solely because they didn't fit the reading formula grade ranges published in Appendix A. Yes, if you read the fine print, it said to use reading formulas as just one of three factors but anyone familiar with the education world could have predicted that some administrators would seize on the quantitative measure and require it, as indeed some have.