Reader DC Group Policy Deploying 2015 version

Here's what I've done to deploy Reader DC to a test machine so far:

-Apply for the Distribution License, Get the approval email, Download the .exe (Windows 10) from the email link provided. (https://get.adobe.com/reader/enterprise/)

-Extract the .exe into it's pieces (msi, msp, ini(2), exe, cab) into a directory let's call "AcroRD21_007"

-Copy AcroRD21_007 folder to a Network share, let's call it "\\SHARE\Deployables\"

-Downloaded/Installed Acrobat Customization Wizard DC

-Within the Wizard: File>Open Package \\SHARE\Deployables\AcroRD21_007\AcroRead.msi

-Make my changes, Transform>Generate Transform.

-Verified Setup.ini has the changes:

-----------

[Startup]
RequireMSI=3.1
Require64BitVC10RT=1
CmdLine=/sall /rs

[Product]
PATCH=AcroRdrDCUpd2100720099.msp
msi=AcroRead.msi

-----------

-Configured the GPO with the help of this link: (https://www.adobe.com/devnet-docs/acrobatetk/tools/DesktopDeployment/gpo.html). Ensuring that I specified the Transformation file created by the Wizard (AcroRead.mst)

-Assigned the Policy to the OU my test machine is in.

-Forced gpupdate on target machine.

Initially, without going through all these steps, I could get the .msi to deploy to the target machine, but it was only 2015 version, and any attempt to upgrade would prompt an "Error: 111100". I suspected I needed to learn more about these .ini files. That's when I stumbled upon the Customization Wizard. 

Now I'm exactly where I started. It installs 2015 version, with no ability to upgrade. Same Error. What am I missing?

Each attempt at installing is to a clean target machine (never had Adobe installed).

All input is appreciated.