the problem is that this was replied and explained multiple times but it seems it is still not clear.
Nobody took any purchases away, they order of the planes just changed, nothing more.
So whatever was the fifth plane (and all its purchases and characteristics) are now also the same in the fifth plane (with all its purchases and characteristics). Exactly the same details, same specs, same speed, whatever you bought.
The ONLY thing that changed is that the fifth plane before was the Albatros D.V. That plane is now at a different position and the fifth plane is the Fokker Dr.I. It has whatever you purchased for the albatros, same specs, same cost, same everything. Just the plane itself has been moved because the Fokker Dr.I was placed as the worst plane in the list by mistake so in reality you were purchasing things and upgrading the fokker but you were seeing the albatros.