FOs should never be diluted with carrier oils, unless you're using a disreputable supplier.
Some EOs are diluted in carrier oils for skin use, but reputable suppliers will disclose this fact and price the product accordingly. If your supplier is diluting EOs without disclosure, you're wasting your money buying cut-rate EOs. If you are using diluted EOs in your soap, you won't get the strength of scent you need.
EOs and FOs from reputable suppliers do not have saponification values because they don't saponify.
