This Knowledge Base article will attempt to explain the basics of Profile and Cloud to CAD/Curve reporting as well as the effects of using the Best-Fit option where available.  This example is a 2D example, however, the principles apply to 3D as well.

We begin with a part with a profile surface and a tolerance as shown here.

We inspect this profile and obtain the following results.  Note the high peak and the deviation in the broad curve.  The report output is based on specifying a bi-lateral tolerance of 0.2 to A and B and no best-fit selected.  Note that the output is based on the worst case value of available points.  A profile tolerance, referenced to datums, takes into account form, location, and orientation of the inspected shape.

Here, we have applied best-fit to the inspection points.  As a group, they are best-fit to the nominal, attempting to minimize deviation.  Note that very few of the points still lie on the nominal curve.  But, worst case deviation has been minimized.  This output no longer conforms to the tolerance specification since the best-fit has removed the reference to datums A and B.  This output indicates only the form on it's own.  But, by using best-fit, we no longer conform to the print tolerance block.

See Best Fit Profile Reporting example here - https://support.qxcmm.com/portal/en/kb/articles/cloud-to-cad-report-with-best-fit