The 1.2 litre info is the total capacity of the "cooking tray".
For rice, there is a measuring cup included, which corresponds to the capacity of one cup (i.e. 1 classic portion). You can cook up to 6 cups of rice at a time.
The cooking tray is graduated according to the number of cups of rice: e.g. if you want to cook 3 cups of rice, you add the rice and then water up to the "3" mark.
I hope I could answer your question :)