can you proof your statement of the expensive shabracke insteadt of the sheepskin with a (primary)source? Of around 500 paintings I have about the different regiments I have none with the shabracke as you mentioned it.
Like that I can't although I seem to remember an image with the french 3rd hussars using schabraques as late as 1814 in a book, but didn't search thoroughly
What I say is that the way supplies were either in Spain for most of the war and in 1813/1814 it would not be out of hand to think that strict regulation was not available. As an example most hussars had either pelisse or dolman and there were many regulation items unavailable.
The regulation and the actual field dress were anyway very different.