I have a 7.5 month morkie. I was giving her 1/2 cup of royal canin/day split into 3 meals. I noticed she is not interested in eating breakfast or lunch as scheduled. Is this normal for her to want to eat less. But she is still interested in her treats, that hasn't change. She appears to be happy and healthy. Everything is the same except for her appetite.
One thing missing from your comments is her weight so suggesting an amount she would normally eat won't work. Your observation is accurate that for a dog of her size and age her appetitie will level off or even decrease because her growth rate has slowed drastically or even stopped. Actually, I often suggest reducing the number of meals as a way to prevent extra weight gain when growth rate has slowed.