Really Cool Mod! But I found a bug...
I put a 20kJ Battery into a Battery Box hooked up to an MFSU, and let the Battery to drain into the MFSU. This created 800 EU. Once the battery was empty, I took the MFSU and hooked it back up to the Battery box (with the output from the Battery Box severed). The MFSU drained to 192 EU, and created 5MJ in the process.