The truck is stuck dead in my friend's driveway. So I will have to get screen captures tomorrow.

The vehicle is a 2003 Silverado SS, current OS is 12593058, I am trying to flash COS3 03190003.tun.

Step-by-Step to recreate the problem:
1) boot laptop and flashscan V2
2) open EFILive Tune v7.5
3) open COS 03190003.tun
4) cut/paste the VIN from my truck into the VIN text box
5) click Flash menu item (first 2 options are disabled)
6) click 3rd option, 'Program PCM operating system and calibrations'

Software will show a dialog window saying that this requested feature is only available to Commercial and Workshop versions.

7) Click File menu option, click 'Close tuning file' option;
8) Click Flash menu option, click 'Read PCM calibrations' option;
9) Use dialog window to read entire PCM from truck, turn off key, wait countdown, dismiss dialog window
10) Save read PCM calibration to HDD
11) Navigate to B0702 Cat Low Protection Temp, increment temp 1-degree
12) Click Flash menu, Program PCM Calibrations
13) Use dialog window to write PCM calibrations to truck, turn off key, wait countdown, dismiss dialog window
14) Close EFILive.

I am a developer myself, I was very careful in testing to verify USB communication was NOT a factor. I will get screencaps tomorrow.

Mr. P.