How hard is to let our staff edit rate manually before creating a new booking. Otherwise we trigger Emails with the wrong rate. Maybe it would be nice if we can edit the rate manually in this screen http://prntscr.com/3mgov9
If you set your "default status" (under Manage > Setup > Configuration) to one that doesn't send a notification the customer, you can change any details necessary, and only change it to a locked status with a notification attached when you're prepared to send the invoice to the customer. This way, you don't need to worry about the customer receiving the wrong details, as they'll only be sent when you change the status of the invoice.
There are a variety of other workflows that can be set up with similar strategies, such as not requiring staff to immediately enter customer information, or allowing customers to creating a booking without immediately requiring payment.
If you'd like a hand looking over your setup, you can always feel free to email support for assistance.