I've just been playing around with the debug mode in Quest for Glory 2 to try to work out the answers to the priority band puzzle. Using a combination of Alt-P (show priority screen) and Alt-E (show ego stats) I was able to verify that both the scummvm and my original formula are correct. The priority bands are as follows:
0: Black - Lines 0-41
1: Blue - Lines 42-52
2: Green - Lines 53-63
3: Cyan - Lines 64-73
4: Red - Lines 74-84
5: Magenta - Lines 85-94
6: Brown - Lines 95-105
7: Light grey - Lines 106-115
8: Dark grey - Lines 116-126
9: Light blue - Lines 127-137
10: Light green - Lines 138-147
11: Light cyan - Lines 148-158
12: Light red - Lines 159-168
13: Light magenta - Lines 169-179
14: Yellow - Lines 180-189
I have attached an example of the screen shots I took during this process and from which I got the above information.