This is used when you are adding that something may be even more, less, better, worse etc than you have just said. 即使不是更…，虽然没有过多…
- Most of these gizmos are as insecure as any other computer, if not more so.
- Her needs are just as important as yours, if not more so.
You can also say if not impossible/great/forgivable.
- The snow was now two feet deep, making it difficult, if not impossible, to get the car out. (if not impossible = although it was not impossible)
- Although governments and large companies are crucial in addressing conservation issues, the role played by individuals is just as important, if not more so.