Steel Composite beam design

Good day

When doing steel design, and marking a beam as composite.

With no concrete slab over, the beam hasta a design ration over 1.0

With the concrete slab over it, but with the design parameter of CMP = 0, the beam now has a ratio under 1.0 (Pass)

And with the CMP = 1.0 the ratio os around 0.35.

Is it not, that if CMP = 0, staad dones not consider composite?

Does anyone knows why with the concrete slab but with the CMP = 0, the ratio lowers (Passes)

Can anyone please comment?

Thanks

Rafael B from Mexico