Mazda Bongo 2.2 Rocker Cover Gasket

Mazda RF and R2 engine is consider one of their trademark 2.2 diesel engine range, mostly the RF series of engine is using 1 piece of rocker cover gasket in one engine, interestingly we found this Mazda Bongo Brawny which also install with a 2.2 RF series engine, is using 2 pieces of rocker cover gasket.

And it uses 2 pieces rocker cover gasket is not like those rocker cover which design a such have 2 separate cover side by side, but there are actually separate in 2 different layer at the engine just like what you see in above diagram.

So it is curious why the rocker cover have to design as such need to use 2 pieces of gasket? Is it there are any special function for this engine under this design?

In the latest occasion, we found that this engine is use in Nissan Truck SKF2 model.