There seems to be so much conflicting data on this loss I asked my friend Dave Gansz to take a look. Author, (not advertising just a reference):
https://www.amazon.com/Boeing-B-17-P...%3ADavid+Gansz
https://www.amazon.com/Boeing-B-17-P...%3ADavid+Gansz
Dave found the pilot had served with the 96th BG, in roaster as William F Chandler (413th BS)
42-97599 appears to have been a PFF ship, so it seems it got shared between groups on various missions.
Now back to the beginning with the accounts attached from "Losses of the 8th & 9th", p. 394 (attached).
If this is an accurate account we are back to the bombardier being 1st Lt Charles C Nielsen, with the 390BG website data being in error. Sadly Nielsen, Charles C is not found in searching the 390BG database
http://www.390thspace.com/search.php making it impossible to cite his service with this group from that source.