It seems, that I'm recognising something mysterious. I'm scanning one film after an other. After some films I switch off the scanner, take out the SD card, copy the files from the card, erase them on the card, put the card back in the scanner and turn on the scanner again. There is no film in, the color settings are changing, I can see that in the little histogram. OK. He adjusts. I hadn't changed the White bal and green yet. I recognised, that the first value stays always like it was at switch off time. I believe, same to the last value, but the middle value often changes. I hat 256, after switching on it goes to 324 or so.
Second mysteria : I recognized, that in dark shots there was a shine on the capture from the sprocket hole. So I had an inserted film, went back the frame adjust with down arrow five times, checked the scanning window, putted it 2 times more left, went back with up arrow five times. I repeated the back-forth-left adjustment a second time and went back to the recording setting. I also recognised, that the middle value in the histogram was changed, from 256 to 224.
That means be careful if you have many films of the same historic time and vendor and want to scan them all with the same adjustment ( because you figured out that it fits best ) and check if the settings have not changed for every new scan.