The IRS says on https://www.irs.gov/uac/pay-taxes-by...-or-debit-card "Fees differ from those in the table above when you choose the integrated IRS e-file and e-pay option."
They provide a link to https://www.irs.gov/uac/pay-by-debit...hen-you-e-file , which shows a different set of payment providers, with higher fees.
But when I follows those links, they show the lower fees that are summarized on https://www.irs.gov/uac/pay-taxes-by...-or-debit-card .

I have a hard time understanding what is going on. Even if the fees are higher for "integrated file/payments", why would anybody in his right mind pay the higher fee, when the same can be achieved for the lower fee when paid outside the integrated file/pay software? None of the software that I know requires payment when filing a return.