I like to add the sugar once fermentation is well underway. I just reserve 1L or so from the batch, then add that later once I've boiled the sugar in it. It does three things: lowers the size of starter I need, reduces stress on the yeast, and slows total fermentation time. A slower ferment is a colder ferment. Colder ferment means fewer off-flavors.
I know there are a lot of people who do what you do, but I've never found an advantage to it when I tried it.