No. After you've ordered, it is rare to order anything else. You might ask for a refill of a beverage or something like ketchup, but the waiter is not expecting more ordering. It's simply expected by diners that their waiter is there and will help with whatever they need. In Europe you'll wait 20 minutes to get the attention of a waiter for salt or ketchup until your food is cold. Also in Europe this will be described not as dead time waiting for a small thing, but as culture. European culture.