It is interesting that that MACR for Mills includes a map which has an "X" indicating the location of an "Accident", while there is no other reference or mention of an accident in either MACR. The "accident" seems to be roughly were the two planes crashed, as discussed in this previous thread:
http://forum.12oclockhigh.net/showthread.php?t=29905
"both Plowman and Mills crashed between Schwarmstadt and Gilten about a mile apart"
The map may have come from a MACR or after action report by someone in one of the B-24s or with another fighter group who witnessed the "Accident" involving the P-51s.
This link, for example, reports they collided:
https://www.uswarmemorials.org/html/...?PeopleID=7359
Mills:
https://www.americanairmuseum.com/person/163092
Press Release on Mills:
https://www.dpaa.mil/News-Stories/Ne...ar-ii-mills-n/