As
@amd stated, the 5.5% of Spearmint EO in the recipe you used is more than the typical "strong" amount of 5%. That said, since IFRA guidelines on safe usage rates are based on specific components within an ingredient (so, for EOs the IFRA guidelines will address the components within an EO, like carvone and limonene) the only thing I could quickly find on safe usage rates for Spearmint EO for Category 9 (soap), is this pdf for a specific brand of EO, but perhaps it is helpful:
https://www.oand3.com/wp-content/uploads/2018/02/ifra-statement-spearmint-essential-oil-organic.pdfAnother article, that I think does a good job of explaining how IFRA guidlines work for EOs:
https://milesawayfarmww.com/2015/12/14/essentail-oils-a-safety-primer/And, finally, the only IFRA guideline I quickly found with references to Spearmint EO (you might note Category 9 is missing)
https://ifrafragrance.org/standards/IFRA_STD_016.pdf
In the end, you used what most people would detect/smell as a strong level of Spearmint EO, but likely not an unsafe level (at least for one particular brand). Perhaps Soap Queen's sniffer really likes spearmint, whereas yours does not.
Going forward, you have the EO calc to check the EO amounts suggested by recipes of other people, as well as in your own recipes. Personally, I find 3% is my usual, but if I don't like an EO even 1% can be too much for me. I still catch a whiff of patchouli here and there from a small sample bottle that leaked and that I threw away back in December. December...
@amd - teehee - "Lavender Sage, looking at you". I also only notice the scents in my curing soaps that I don't like. How funny.