With respect to the tip flow, with Chip & PIN you would need the final amount before authorizing the transaction so the tip would be added before just as your guide suggests. Chip & PIN terminals in Canada and Europe do just that. They present you with the tip screen (% or amount) before you enter your PIN & finish the transaction. For MSR, just like in restaurants today, they can change the amount after the initial authorization but they also often authorize for about 50% more (to allow for tip) and then do the capture once the server takes the bill from the table and "closes" it with the correct tip.
I can say from personal preference that I would do a double take if a device allowed me to put my card in and finished the transaction and then permitted a change to the charge amount. What is stopping the cashier from adding her own tip once I walk away.