Yes, Daz, I have cockatiel suffering lifelong consequences of a bad wing trim. His hard landings split his vent to the bone. His tail is now immobile and he cannot clean it. Fortunately, he now has a doting mate who does it for him.
When you first get a wing trim, just a few of the primary flight feathers should be trimmed and then the bird should take a test flight . Another feather can be trimmed if need be. Some birds need more feathers trimmed than others do.