Redstone signal weirdness

I'm trying to use a computer to control RotaryCraft CVTs powering an extractor with a redstone signal. However, the CVT seems to see the signal irregularly, If I use a vanilla level to toggle the CVT ratio, it's all good - the extractor suns smoothly between the high torque and high speed modes. But if I use a computer thusly:

rs.setOutput("back",true)

the extractor irregularly jumps between modes, (albeit mostly running the desired mode) as if the redstone signal from the computer is glitchy.

Has anyone seen this, and/or has a workaround of fix?

Bunz

I've heard of cauldron / bukkit servers having problems with redstone.