I think this question may be asked the wrong way. Yes, the german army die allocate some troops to run the concentration camps, but they were an important part of the war industry and the wehrmacht most propably gained a lot more ressources from the camps than it did cost them. One popular example for the importance of forced labour to the german war effort is the Mittelbau Dora Concentration Camp, which was constructed to build weapons like the famous V2-Rockets. Frank Baranowski wrote a book about forced labour camps in that area. I am sorry that i can only point you to a german source: Die verdrängte Vergangenheit. Rüstungsproduktion und Zwangsarbeit in Nordthüringen (2000)