@Maxisme
What is working fine? There is a bug.
I don't really know what your example is doing, what I see here is that when one attribute value changes compute function is called two times with the same values, you may see here:
that should not be the case. What I wanted it to link compute result values and scope attribute. There was an issue created to address the problem: https://github.com/bitovi/canjs/issues/646