Is there an analytical description of the NACA 642-015A profile? While searching for symmetric profiles I stumbled across different definitions (point-clouds) of the NACA 642-015A profile.


http://airfoiltools.com/airfoil/seligdatfile?airfoil=n64015a-il
http://www.airfoildb.com/airfoils/418.dat


The figure below (skewed) shows the difference in percent chord on the secondary axis (green markers).



What causes these differences and is there a analytical description I could use to create a point-cloud with higher resolution.

Another question is:
The NACA Reports I could find via Google all feature the NACA 642-015 (without the "A"). The difference between NACA 642-015A and NACA 642-015 is an increased thickness of the A-version towards the trailing edge.
Who introduced or developed the A-version?
This report seems to include a reference to an analytical description of 6-series airfoils



On your second question: found this reference in Synthesis Of Subsonic Airplane Design by E. Torenbeek:


  A modification to the standard series is the A-series in which the sharp trailing edge angle is replaced by a larger one, resulting from straight contours which run from 80% chord backwards.


The paragraph contains a reference to "Theoretical and experimental data for a number of NACA 64-series airfoil sections" which turns out to be NACA LM R6J01