Not sure what exactly you mean to be honest. I haven't got a problem with my screens. What EricL says is correct. If you have the Enegry Off on the OSD menu, then you can use the Magicinfo pro software to swicth OFF and ON.
In any case you make reference to MDC, this is a serial connection and that should work. I have used it few times. It maybe you have mixed version? I am not sure.
The third thing you may be able to have a look at is the Time function. Is this what you want? Activate and Inactive the timings, but if you do this, then with proper power OFF the unit will loose it's Time settings.
Bill