The getCompetitivePricing (SellingPartnerApi\Api\ProductPricingV0Api) call has very inaccurate / incomplete information.
If you try and do a call on Asin, “9400745591” for example there are 4 used offers and 4 new offers. The API reflects this in the number_of_offer_listings section. However, it only returns the price for new despite being higher than used.
I would not rely on this data from this API, I have many examples and you will end up with wrong information.