okay let me clear my head, from what I understand a mbc will allow you to build boost to a certain point, once that point is hit the mechanism inside the mbc will open an allow pressure through to your waste gate actuator thereby opening the waste gate and limiting boost to what ever it is you have it set at. Now if you set an mbc up to whatever it is you want fuel cut at, for me I'll use 16 psi, and place it before the pressure sensor but after the manifold. When the manifold reads 16 psi, the mbc will allow pressure through to the pressure sensor, and since the pressure sensor kicks on at 10-12 psi 16 psi will be more than enough to kick it into Fuel cut mode. Now just correct me if I'm wrong as to how an mbc works, because if it works the way I think it does, the mbc could very well act as an fcd. I would think turning the setting down would just allow you to hit fuel cut at whatever the factory setting is, because you'd be allowing any pressure over what you have it set at through the mbc, example you set it at 5 psi anything over 5 psi is going to get read at the pressure sensor.