On the ILF, you drew 10-20# less than you usually draw, and probably on a bow that was quite a bit longer. Certainly should feel smoother. ILF risers have very little to do with perceived smoothness, except perhaps for their influence on overall bow length. Limbs a whole lot more via design, length and poundage.
I don't think that the limb pad angle is standardized across all Ilf riser makers (and they're different for different length risers) so to the extent those vary a tad, you could expect some performance difference, but not enough to notice. You will notice the difference between different length risers (because they make different length bows), but very little difference between different risers of the same length. Too, riser weight can affect the feel of the bow at the shot. Some like the warmth of wood; others like the more substantial mass weight one can get out of or add to metal risers.