In the AUTHOR tag in SAP we specify the author of the Atari version, and STIL is for the original composer. For example AUTHOR of /Composers/Billyard_Adam/Henri.sap is Adam Billyard and Johann Sebastian Bach 
 can be found in STIL. This is consistent with NAME "Henri" (Atari music) and TITLE "Two-Part Invention No.13, in A minor (BWV 784)" in STIL.