You are as good as you can get with that meter. Remember there is a tolerance of +-2% with that meter So just because things look perfect, don't mean they are. You will need to spend $8-$10,000 USD for a meter that can get you close to perfect, but in the end, the display is a consumer display and is FAR from perfect. Those tiny little bibs in brightness at one stimulus level is not going to be seen when you watch content. You did a great job, now sit back and watch some movies!