You are correct: The draft P4P manual states that there are no modifications from HEDIS. The differences you see are the result of anticipated P4P changes and updates to the Volume 2 CHL measure, per the HEDIS 2015 Volume 2 Technical Update released on October 1, 2014, at www.ncqa.org.
The HEDIS technical update changes aligns the HEDIS CHL measure specifications and value sets with the September release of the P4P CHL measure and value sets. We included these updates in the September release of MY 2014 P4P to reduce the edits that P4P organizations must apply with the December release.
ALL 2014