Again ... about 6 Hours ago. N-Scrypt running well the last 15 Hours, then in the Night it switched to X13 and again back to N-Scrypt. 5 of my GPUs go off and 1 got the turn and was running well in the right speed

Any solution for this? Missing 6 Hours every Day hurts.
Have you tested X13 on its own first to see if it's stable? (non-multiswitch port 3337)
I think it's wise with this multiswitching to be a little more conservative with how hard you push the GPUs, since you add the variable of switching. Keep your engine, clock, intensity, slightly lower than you would if you're mining only 1 algorithm. After you find settings that allow smooth switching, slowly tweak from there.