I can’t speak internationally or legally but from what I know from friends in similar jobs daily prices changes aren’t uncommon. The reason and when it happens often is normally the start of the day when there is a new batch of tickets. They don’t go up instantly and multiple 100s of tickets normally take a couple hours to get placed depending on how many/busy staff are.

Main thing is e-ink’s don’t really make this significantly better or worse. I personally think they are neat for the end worker. The problem is that this is allowed or not enforced well.