This might be useful:
https://www.pcmag.com/roundup/354518/best-credit-card-processing-services
The itch.io admin Leafy would need to contact them and get additional info and provide the data for them to respond with accurate pricing strategies.
The 'race to the bottom' in pricing does a disservice for both indie devs and gamers alike. Gamers can't tell what is 'good' or not based on price alone. Free games that are fun and amazing (WarFrame) or paid games that are absolute exploitative gamblebox crap (Mortal Kombat 11).