Hi,
I tried to read your mail to find out what you did and why you did it, but I failed miserably. We wanted that you test a setup without batman-adv that uses static routes between nodes in adhoc mode. This would be help us to find out whether batman-adv is the reason for the bandwidth drop or your hardware. And the static routes should help to recreate the multi-hop tests.
Maybe you can restructure the explanations of your setup (and which results you saw with each setup).
Kind regards, Sven