Pro sites checkout page customization only on Login area?

I understand you allow us to edit the Checkout page, however, my edits do not appear on the actual checkout page, but the login page.

(Using Stripe Gateway).

Is this a bug with Stripe? Or does this function with other gateways? Or am i simply bugged.

Again – just to be clear.

Edits to page appear only on that page when LOGIN info is displayed. Not on Select a payment plan display.