how to minimize edge tolerance?

I'm importing a step file containing very bad PCurves. I'm doing the following

For each wire:
- Do a wire fix (ShapeFix_Wire). This simply raises the edge and vertex tolerances in order to meet the distance between pcurve and 3dcurve
- Go through all edges and, if the edge length and edge tolerance are similar in size, I throw away the pcurve and let ShapeFix_Edge recreate it

Now I got good pcurves but the edge tolerances still are very bad. Is there a possibility in OCC already to minimize the edge and vertex tolerances?