Just FYI, J-851 here:
https://catalog.archives.gov/id/131495547?objectPage=4
As for 357th FS on 15 Apr 1944:
https://catalog.archives.gov/id/4696...ect-thumb--998
On 15 April 1944 just one He-177 loss at Fassberg due to 'Betriebsstörung'? (IV./KG 100).
There also was a Do-217 loss there due to 'Tiefangriff' (E. Stelle Reichlin).
Leendert