U have not mentioned the quantity of the sugar.
Please make sure that recipes are checked after writing.Can u also make sure that when u correct ur recipe u write the ingredients also???
If you are a good cook or if you know atleast the basics of cooking then you just have to use your common sense. Sweetness is a factor that can vary according to a person`s taste. So use sugar depending on the sweetness that you require. There`s nothing wrong with the recipe.
Actually this is a good recipe its very easy and tastes yummy,i too prepare payasam with milk in the same way.U see that u ve roasted semiya well and add sugar as u need sweetness( 1 or 1.5 cups of sugar is morethan enough).