The way I did that was first by doing the top grind with a flat platen. Next I flat ground the primary straight across toward the tip stopping a tad after reaching that section meeting the tip. Don't turn the blade at all to grind the sevtion at the tip! Then I went over that section I just flat ground with a 10" wheel followed by flat grinding the very tip section to the desired grind height. As long as you are consistent scribing your lines and grinding to those lines it should come out right.
If you flat grind it all you won't get the same effect. You'll get something more like what you see on a japanese tanto or katana where the kissaki meets the rest of the edge. Good luck!