Surgery outcomes depend on (1) the skill of the surgeon, (2) what the patient brings to the table, and (3) a little luck. In my mind, (2) is the most important. If you're bringing the surgeon a fairly flat forehead to begin with, you'll stand a really good chance of ending up with that "perfect" flat forehead. If you're bringing in a caveman brow, it's unlikely that any surgeon will be able to make it perfectly flat. He or she will make it more feminine, but perhaps might not be able to provide that ideal smooth surface.
Even some of the "best case" pictures on the web sites of surgeons who perform type 3 forehead reconstructions don't show a flat forehead. The results are dramatic, but not always perfect.
So to answer your question, there's a chance that a type 3 forehead reconstruction won't give you that flat line that so many people seem to chase these days. It's not so much surgeon-dependent as patient-dependent. A type 3 will give you the best chance of achieving that flat forehead though. What's your starting point?