Hi Terry,
Yes, this scanner has the ability to turn off all color controls - which I have done. I even found a button to reset everything to factory.
I am using the R070919 target. On the scan from two years ago, the A8 patch reads 129,44,46. On the recent scans it reads 177,32,67 - which Prism flags as out of range. The gray scale is coming in almost perfect, though it is now flagging the white and black patches. Looking at the target overall, it appears that the saturation has been kicked up; but the driver/interface is set for no correction.
I am getting better results [read: fewer flagged patches] when I scan in 48bit instead of 24bit (though the older scans were 24bit and had fewer flagged patches). I see that Vuescan has a free trial, I may give that a shot.