It's string action was way too high and everything I've tried to do to solve it ends up with the strings buzzing at 15th fret and above. Making saddle adjustments wasn't solving it. I've tried shimming it and it reduced the string height a bit, not enough. It seemed to result in too much correction and fretting out or not enough and fret buzz. I have one of those notched aluminum rulers to measure how flat the neck is and it's perfectly flat. I tried adding some bow to the neck but turning the truss rod in either direction isn't working. I can make it even flatter or maybe add a very slight back bow but I can't get any forward bow, even under string tension. I have a fret rocker tool, the frets have been measured and leveled/polished so it's not a high fret problem. Any ideas?