Removing those small flakes on either side of the one you really want gone, will help the main one travel.(less energy lost)When you isolate your platform,however small it may be,before you hit it,(or miss it 10 times)
grind down the areas on either side of the platform,( This doesn't take much,just a little)thus giving them some strength.This allows the flake to release in a controlled manner and not just running out at random.
Something else to think on is, how well you control your rock at the time of contact. Sometimes we drop our hand just at the point of contact with the billet,this completely changes the angle of the hit. This will cause a flake travel to terminate early as the angle gets to flat. Try to focus on that and keeping that rock hand steady through the hit.
A little trick that sometimes helps me with hitting: Before you make your swing,push the billet into the platform a couple times lightly, Kinda just touch it,giving your muscle some memory,then take your swing.