German bread flour (type 812)

Hi there, I am an Australian living in Germany and have begun sourdough bread baking.

I am using what is known in Germany as “Weizenmehl type 812“ which, from the research I’ve done, is the closest to bread flour that is available.

Howdver, I read this great post the other on http://hanseata.blogspot.de/2012/05/my-pantry-flour-type-translation.html that outlined type 812 flour as “type 812 is a mixture of 2 parts Typ 1050 + 1 part Typ 405, there is no US-equivalent. I would use bread flour and a little bit whole wheat (same as the substitute for Typ 1050.)” and then also goes on to say, under substitutes, “German Typ 812: 77% bread flour + 23 % whole wheat”. 

 Now I am feeling a little confused. Is Type 812 flour the best equiavalent for bread flour? Does it contain some whole wheat flour? I just want to understand the content of this flour, because if it does contain some whole wheat it would be good to know so I can workout exactly what my bread is make up is to give me a better of proof times etc. (Particularly as the higher the whole wheat content, the faster is usually seems to prove).

Thanks in advance to anyone who can help.