So I'm obviously very new at this so please excuse my complete lack of knowledge but here goes ... Question .. my understanding is that superfatting is when we add more oil then the lye can saponify so those extra oils are left behind in the soap, thus your skin is abe to absorb those properties and benefit from them? Is that correct? So ... what would be the difference in adding the SF at trace or mixing it in with all of the oils be for mixing with lye (other then it decreases the likelihood that you will forget to add it - which would have been very beneficial to me today!!)
That is what SF is but at trace, the lye is still very active and it will saponify what ever it wants. Saving the SF to add at traces does absolutely nothing besides make it easier to forget.
The only time you can control what oil you choose to be the SF is if you are making HP. Since the soap is completely saponified, there isn't any lye left to eat your SF oil when it is added.