...when we're superfatting... aren't we left with a soap that has extra oils?...
A bit OT, but I wanted to respond to this thought --
Yes, superfat is extra fat that is technically not saponified. But I think the usual assumption is all the superfat in a soap actually remains on the skin and that's not accurate.
Only a small amount of superfat actually does that if you superfat at typical levels. Not enough to replace the need for lotion or other leave-on moisturizer if you have dry skin.
Most of the superfat bonds with the soap molecules, just like natural fats from the skin, when the soap is mixed with water. This combination forms a water-based emulsion. This emulsion largely washes away when you rinse the skin, which means the fats go down the drain, not stay on your skin.
It's more useful to think of superfat as an ingredient that reduces the cleansing ability and any potential harshness of a particular soap.
If your soap is already mild to the skin and already a gentle cleanser due to your choice of fats, there's not a lot of reason to raise the superfat to make it milder yet. The main result of using a higher superfat in an already gentle, mild soap is to reduce the amount of lather.
If you actually want a significant amount of superfat to stick to the skin, you'll need to raise the superfat amount a lot higher than I hear most people say they use when this info is shared on this forum (not counting salt bars). Some say the fashion in Europe is for a much higher superfat even in regular bath soap, so YMMV if you look outside SMF for info about superfat amounts.
One person who briefly posted on SMF some months ago said they made soap that I calculated had around 50% superfat. The poster said it left visible traces of fat on the skin. So it's possible to superfat enough to leave an obvious amount of fat on the skin. But the usual superfat levels mentioned here aren't high enough to do that.