John
Checking what Donald Caldwell states in Day Fighters in Defence of the Reich for May 12th, he states on page 292 that ZG 26 made 5 claims that day and lost 4 Me 410. On page 293 he refutes that statement by listing (in total) 4 claims and 5 losses, ie a total reverse of what he says on his previous page....
However he lists the first claim (a single B-17) to have been made for the inbound raid between appx 11.30 to 13.30H by II./ZG 26. On the return flight II./ZG 26 again scores against a single B-17, while I./ZG 26 claims 2 B-24. These three claims are between 13.00 and 16.00H.
Exactly why Caldwell makes two different statements on page 292 and 293 is something I have no opinion about, although I can make a guess, but the important deduction regarding this discussion is that you seems to refer in your statement to the SECOND claim by ZG 26 (you say 2./ZG 26 and Caldwell says II./ZG 26 and I don't know which is correct).
Perhaps you can clarify by giving your complete ZG 26 version for that fateful day?
Cheers
Stig