When I enter the numbers you actually used, based on the information provided up the the most recent post, into
SoapBuilder (SoapmakingFriend Calculator), the result I get is that you have a soap with a -8% SF. (Unless I also made an error.)
See this link for the results i got:
Soapmaking Recipe Builder & Lye Calculator
Potentially you could hold onto this soap for a very long time and eventually the lye would neutralize, but is it worth it to wait until that happens for all the bars of soap? If it were me, I'd probably grate it up and just use it in a rebatch mixed with a new soap batter that has a higher SF than I normally use, and give that a nice long cure, to be sure the lye in the shreds interact with the rest of the soap to even out the lye in the new soap (while the curing process does it's thing forming the crystalline structures). The problem with that is that when it's a large batch of soap being grated, incorporating into a new batch (my preferred method to use up soap scraps), it takes a long time to use it up if I only use a little at a time for visual interest. Or I could make a huge batch to use it all up at once. And how much soap do I really want to have lying around curing at one time?
I do agree that holding onto a couple of bars which are clearly labeled as to the Negative SF and the date made, to re-evaluate periodically, is worth doing as long as you know you will go back to it periodically to re-evaluate. Of course if you do that and go ahead and rebatch the rest of the entire batch of soap all at once, your end result calculations may be even more difficult, so just adding the missing oil won't give you the SF you started out with as your goal, but at least it will be in the positive range and not the negative range.
When I was new to soapmaking, I rebatched every time I made an error like this. Eventually I learned to just toss out the lost causes and move on. That's not saying this is a lost cause, as it is a learning opportunity, but for me even tossing something out is a learning opportunity as well.