Your question seems to conflate utility patents with design patents. An issued design patent starts with a "D", as in D123,456. That covers only ornamental design. A utility patent covers function. Because you're asking about a utility patent, the ornamental design cannot be protected by that patent. Of course, there may be a design patent out there, or you may be referencing a functional design (like the design of a circuit).
Because of "continuation practice", it is possible to claim one group of things in a first filing, and then claim a second group of things in a second filing based on the original patent filing. So for example, I might file for a patent on the car. In my first application, I might seek to claim only the muffler. In the second application (which is a continuation of the first), I might seek to claim the internal combustion engine, etc. As long as the original patent application enabled a person of ordinary skill in the art to build it, it can be claimed in a timely-filed continuation.
Frequently, the inventor and patent lawyer aren't sure which claims will issue when they file the patent application. They write the title and abstract so that they generally describe the entire device and most of the possible claims. After a lot of back and forth with the examiner, a set of claims is allowed that quite often no longer matches the title or abstract. There is nothing inherently improper in doing that in the US, though best practices would be to seek to amend the title to better match the claims. Perhaps more importantly, the uninformed part of the anti-patent lobby often looks to the title and abstract to describe a patent. So an abstract that reads "A method for vehicular propulsion is described herein" may be combined with claims that cover only regenerative braking, but because many people don't understand that the claims -- and not the abstract -- describe what is protected by the issued patent, they think that the patent covers all methods for vehicular propulsion. They then get bent out of shape over the idea that another low quality patent has issued covering technology that is 100 years old. For that reason alone, it is important to the inventor community that abstracts accurately describe the invention.