It is very important that they don’t miss any areas. Touch-ups won’t help. And if they do not do a proper job, it all adds up, and it gets very unlikely that you will have uniform growth.
I had 5 arm treatments and now the result is patchy. After more than a year, it hasn’t gotten better. As a last resort, today I’ve started Rogaine. You can read my previous posts about my experience.
16j using an 18mm spot size is a good starting point. If you skin can tolerate 18 or 20j even better.
Five treatments is not enough to see good results. Minimum would be six, some people need twice that. Guys generally need more due to more testosterone in the body.
16J on the largest 18mm spot size is a pretty high setting. The max is 20J on 18mm. If the spot size is smaller than that (i.e. 15mm, 12mm, etc), the overall power decreases greatly. So you should try to get treated at 18mm spot size if possible. Of course, you need to make sure your skin can handle these settings.
What specific areas are you treating? Is the hair coarse?
If you have an ethnic background, you still have underlying pigment even if you look light. So keep that in mind.