1/ To prevent such a feeling, we've included this disclaimer at the beginning of the post, (i) to state where we stand vs Stripe, (ii) the source data is Stripe's pricing, happy to share more details about the hypothesis
"Disclaimer: This analysis is based on Stripe’s public pricing as of July 21, 2022. Some merchants may be able to negotiate fees or benefit from grandfathered plans. Lago partners with 'Stripe Payments' and can be used as a complement or replacement of 'Stripe Billing'."
2/ I think below comments (to be clear: comments from people completely unrelated to Lago) show how you can reach 4 to 8%. It's also one of the reasons why 'Paddle' is an attractive solution in Europe, it's an all-in-one solution that takes 5-6% on revenue and provides subscription management, payments, invoicing, tax management.
Let us know if you need more info, or if you have feedback on what we could have done differently. In any case, I genuinely appreciate that you took the time to comment!