just replied to your other topic... You could have put them both in one topic by the way.
I'm not sure exactly how much food they need each day. Do they clean the dish out pretty quickly each time? Is there any left between feedings? Are the birds continuing to gain weight? To they look or feel thin? These are things to consider. If they're eating ALL their food pretty greedily, you might try adding a little and see if they continue to eat it all. Some people provide food ALL day, some don't. Some birds will overeat, some wont.
I would think if... when you feed them, they go crazy as if they're starving, they could use a little more food each day. But if a few hours after feeding them their dish isn't clean, or there's even any left at the next feeding, then I'd say they're getting plenty. I guess what I'm saying is test things out a little and use your best judgment.
Depending on how gross their food dish gets, you might not need to clean it out each time. But you do want to keep their water dish clean as often as possible. Clean water is good. But if their food dish is getting muddy like... then it sure doesn't hurt to clean it out so it doesn't get moldy.
You might try keeping the food and water on different sides of the cage. This helps prevent some of the mess... keeps more of the water on one side and more of the food on one side. If they're right next to each other you end up with a big mess. They kind of like eating a little, drinking a little, eating a little, drinking a little... etc... and you end up with food in the water and water in the food.