I have had my 3 miners working with the multi-alo switching configs for about 3 days now pretty steady. I haven't seen it switch to Scrypt or Scrypt-N yet so I dont know how stable that would be with the switching. I'm using sgminer 5.0 06062014 build
I've tried using the same build and the same copied 280x conf of yours, and all I'm getting is rejects, HW errors, & "Share above target" for X11 & X13.
X11 & Scrypt-N works under my conf, but Scrypt-N slow as balls at 173KH/s vs 1.83Mh/s it's supposed to be, and X13 Still produces 100% rejects & HW errors.
I'm missing something. What O/S & Driver versions are you using? Ram size & VM setting?