We have had a few conversations lately in other threads about IRFA and how to interpret its recommendations, so I want to throw in this for the good of all --
IRFA recommendations are based on what works for skin safety, not on what works for making good soap. If you take IRFA to its logical extreme, you could theoretically make a "soap" with 100% of certain fragrances, and ... well ... it would smell nice, be safe on skin, but it wouldn't be soap, right?
When the IRFA gets closer to what seems reasonable, it's easy to be deceived into thinking that a max dosage of, say, 10% will be fine. But that's not necessarily true.
Based on a few experiences, I've learned to not use fragrance over about 6% in soap, even if the IRFA recommendation is much higher than that. I would expect to have trouble with a soap batch if I added a scent at 10% -- weeping of the fragrance, discoloration, unusual softness, and possibly even emulsion failure in the mold.
If I want more scent strength than what 6% can provide, I don't just keep upping the % of that FO -- I look for another fragrance that works better at a lower dose.