About this detail of the Tiger
With reference to the kit "Battle of Kharkov Tiger" : some of its painting guides specify "RAL 7021" for the turret bin, while the rest of the tank has other colours. This is unexpected, but it's what we see in photos of these actual tanks.
When these Tigers were constructed (December 1942 / January 1943), no standard turret bin had yet been created for the Tiger 1. The factory was shipping new tanks with a Pz.3 bin crudely attached.
A larger rectangular bin was soon designed and bins were sent to most of the units that had Tigers. I don't know who manufactured it; possibly a subcontractor.
It's not clear where the Tigers were when their new bins arrived; in the training school at Paderborn or on the front lines. But the photographs make two things very clear: the tanks had already been painted, and even camouflaged, when the bins arrived; and the bins were very dark in colour.
Some units attached the new bins without painting them to match the tank. When we ask what dark colour would have been applied to a new part, intended for a Panzer whose true colour was not known, the obvious answer is "Dunkelgrau", known officially as RAL 7021. It was the default overall colour for Panzers at the time. So, it was simply unfortunate that the bins did not match up with the tanks.