On page 38 of his book 'Frontal durch die Bomberpulks' Fritz Engau (I./JG 11) writes;
"...When I arrived at I./JG 11 in early 1944 a number of our Fw 190s, including the Kommandeur's machine, had been sprayed in a light grey scheme overall, toning down the usual mottle finish, while on all our machines the Haken- and Balkenkreuze were only barely visible ('schwach erkennbar')...It has often been imagined that this unusual finish served as 'camouflage' (in 'English' in the German text) so that our opponents would find it harder to pick us out as German machines in the air..[..] You could hardly disguise the distinctive form of the Fw 190 or the Bf 109 in the air. In addition all JG 11 fighters displayed a yellow fuselage band which was highly visible. Ultimately the reasons for adopting the finish were obscure and it can be supposed with a certain degree of certainty they probably had more to do with testing of colours/paint finishes- than any other consideration. Certainly at the time the subject was not one we pilots discussed....."
The images below are just two from a series that appear in the outstanding Jochen Prien Jagdfliegerverbände series (Volume 13, 1944 - Defending the West) depicting III./JG 11 Fw 190s with over-painted crosses. Note on the 'overhead' photo the wing crosses are just visible...
Also on this blog;
JG 11 Gustavs defending the Reich 1943, Jochen Prien's Jagdfliegerverbände series
'Frontal durch die Bomberpulks' Fritz Engau (I./JG 11)