Parametric sweep: how to add one step

Hi,

I have run a parametric sweep calculation on a geometrical parameter. Now I want to add only one step without re-running all steps already solved.
E.g. results for parameter "A = 1,8,15,30,60". I want to get the result also for "A=45,80"
Is it possible? How to do it?

thanks for your help
BR

Stefano