Upgrading 1.3.7.1 to 1.3.9d, and the "Attributes Separate Stock" module

We just upgraded our 1.3.7.1 install to 1.3.9d. We use two add-ons, "Attributes Separate Stock" and "Better Together." We easily upgraded Better Together, but there is no upgrade available for Attributes Separate Stock module since 1.3.5.

(Note: Attributes Separate Stock should not be confused with Attributes by Stock, which serves a different purpose. URLs:

Attributes Separate Stock:
http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=326

Stock by Attributes
http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=310)

We went ahead with the upgrade by starting with a fresh copy of 1.3.9d, applying the latest Better Together, and running the DB upgrade scripts. All is working well, but we do need to find a way to get the Attributes Separate Stock module running before we can proceed.

I compared all the files included with the module to the same files included with the base 1.3.5.1 files, then compared those same files with their 1.39d counterparts. At least one file was changed pretty significantly between 1.3.7.1 and 1.3.9d, and in ways that conflict with the changes made by Attributes Separate Stock.

Has anyone upgraded to 1.3.9 and is successfully using Attributes Separate Stock? Or is there another module that would allow us to automatically keep track of quantities by attribute? We're using ZenCart to sell concert tickets which feature section-based seating, so we need to control the number of tickets sold per section, and disable the attributes as the sections are sold out.

Any help or guidance would be greatly appreciated!

Erik