The first thing you need to do is ensure you are running the latest software - V7 and V8, along with firmware. Given you've had the product for some time, everything you were shipped with will be out of date. We had a major software update in March, and 2 additional updates already in April.
This document will provide you with the details on how to find your details for each relevant component.
http://support.efilive.com/kb_article.php?ref=7141-YSDK-3270
From our website,
http://www.efilive.com/index.php?option=com_content&view=article&id=48&Itemid=133 you will find the relevant software to install.
At the end of the process you need to be running
V7.5.7 Build 203
V8.2.1 Build 194
FlashScan/AutoCal firmware V2.07.26
The installation of the software isn't too difficult, however depending on your ability to navigate computers and confidence, the firmware/bootblock process maybe a little more complex. This document will walk you through that process
http://support.efilive.com/kb_article.php?ref=7243-SFGL-2949.
Rather than navigate through the scan tool and tune tool manuals, you may find it easier to follow the download your tune instructions available in the Dodge Cummins Quick start guide. You will find this PDF document by clicking on your windows start button, then All Programs, then EFILive, then V8, then Documents. It will be listed there as Dodge Cummins Quick start.pdf. This was a much simpler document to get Cummins customers up and running quickly. The information in this document applies equally to Duramax.
While I appreciate you are not happy at this point of time with ATP, you will speed up the process if you can ensure your software/firmware matches the current release.
Cheers
Cindy