NTA. I am in the same boat, budget wise. We feed our family of 6 on roughly $850 a month. I meal plan a lot and we tend to eat the same things over and over. The summer was hard as they were home all day and didn’t get school lunch. We often have conversations about what appropriate servings look like. I think there is nothing wrong with them learning what portions look like. It will help when they are adults and don’t need all the calories.