This paint represents the color variant featured in the color chart included in the 1938 edition of L.Dv. 521/1 regulations.

According to official regulations, standard color of Luftwaffe aircraft cockpits/crew compartments from ca. mid-1941, but in practice already used for this purpose from ca. mid-1940 and in case of some aircraft even in the pre-war period (i.e. specified as color of Do 17 E & F crew compartments in 1937).
According to official regulations, standard color of Luftwaffe aircraft interior surfaces from the summer of 1944.
A good match to the ‘Eggplant Grey’ color used for painting upper surfaces of some modern Russian strike aircraft (Su-25SM, Su-30SM, Su-34, Su-35).