I did a project using a large set of short animated poses that had to join seamlessly.  I found that when using IK with pose dots that you do have to be consistant.  Poses memorized with IK on can give a different result when applied to a figure with IK off. It will cause hands and feet to flip around, mainly.

Another thing I ran into is that parameter dials seem to report the user set value, even if IK has changed that value.  We were dealing with precise angular measurements, so I pretty much had to turn IK off, as it was preventing Poser from reporting correct values.