Are you still cycling or have an established tank? Ammonia is one of those wonderful toxins where we don't want to see any in the tank at all. All you need to know is what color is negative and if you see something different, you know its PWC time! I can't remember off the top of my head what the color chart looks like but seem to remember yellow was negative for ammonia.
Frankly both the ammonia and nitrIte tests are almost worthless except during cycling. If you have anything over zero in an established tank there is probably a good reason, and 90% of the time the fix is a large PWC to help correct the symptoms. Of the FW Master test kit I only occasionally use the nitrAte test to get a snapshot of how high they are (I have a planted tank), but even that's only occasional. It's great during cycling, but really doesn't have much use after that point.