While I can see how this behaviour of PayPal is close to credit cards, I cannot see how they can show an amount that may be incorrect - they could just ask the

While I can see how this behaviour of PayPal is close to credit cards, I cannot see how they can show an amount that may be incorrect - they could just ask the shop whether the amount is final or not and indicate that in some way. I wouldn't be astonished to see chargebacks (by buyers who think they were overcharged) resulting from this - that can hardly be in anyones interest.