1. Since traveler v2.0, we does not allow to use deposit by amount anymore because of some security when calculate total price.
2. You can use Poedit to change that words:
3. Currently, extra service display with default value is 0. If people want to hire it, they select other value for it then theme will count total price.
4. As we know, almost of our customer has set [service] price are included parking price. that mean when they hire a service (ex: hire a hotel room), they will have free parking place.