This might help:
Start XP12, load IXEG, NAV1=101.09 (Ignore red colour in window, as suspected, just a reflection).
Set both NAV to 115, quit XP12, start XP12, load IXEG, NAV1=101.09, NAV2=114.95
Set IXEG preferences to ready to fly, NAV1=101.09, NAV2= 113.90
Set IXEG preferences to cold and dark, NAV1=101.09, NAV2= 112.85
Set IXEG preferences to ready to fly, NAV1=101.09, NAV2= 111.80
Changing the IXEG preferences in this way reduces the NAV2 reading by 1.05 each time. (sorry, pics came up in reverse order)