I'm doing one of my favourite things; internet window shopping for cockatiel items

I see on sale some palm oil, and since I've seen it constantly mentioned for the bigger birds such as 'toos and Greys, I click on it to see what it is
Now the 'size recommendation' the site gives (this is a 4 point sale indicating if an item is recommended for a bird of a specific size, i.e. if a toy would be okay for a budgie. If it has the number 4, for Macaws and Large Cockatoos, next to it, chances are it is not right for the li'le blue one) says that it would be okay for cockatiels
Is giving palm oil to cockatiels recommended? How much should be given? Is it a rare treat or a very very small dose for nutricional purposes?