E67 Will Not Obey Commanded Idle! (files attached)

[chevyspence]

*EDIT* Changed title once I realized what was going on. The tune/OS 12638778 in the GMPP E67 controllers have a known issue of not being able to get the idle rpm to go below 875, regardless of ANY of the parameters we have access to (EFI live nor HPT) I found a couple threads of work-arounds on HPT forum but wondering if anyone here with EFI Live has successfully solved this problem? Is there an earlier version of 12638778 out there that does not have this mystery idle rpm limit?

hopefully these reference links are ok...
Post #9 in this first one sounds promising: https://forum.hptuners.com/showthrea...igh-Idle-Issue
https://forum.hptuners.com/showthrea...e-stuck-850rpm
https://forum.hptuners.com/showthrea...-ls3-high-idle

Original post:

Working on a customers LSX376-525 with 2.9l Whipple and something is preventing the throttle blade from trying to close to drop idle speed to the commanded value. Timing is not being pulled to try to help either (real-time values are matching B5104 base idle spark table). It either doesn't know its 100+rpm too high, or it just doesn't care lol.
I suspected B1829 Minimum Idle Airflow, but cutting the values around the idle range in half didn't change anything. Any idea what I am missing? Thanks!
Log and tune files:
RevT min airflow TEST.ctz
idle park.efi