Turning the standpipe over like that won't raise the water level in your tank, it will only raise the level in your overflow, and since you have what sounds like a Durso-style standpipe, your tank may run louder.
If you don't like where your water level is, you'll need to glue some strips of 1/8" acrylic sheet to the O/F so it effectively raises the level of the "teeth". This will raise the water level in the DT up to the point where it spills over into the O/F. Think of it as making a dam higher...the higher the dam, the higher the water level.
Why do you want to raise the level? It looks OK to me, or are you trying to make the level come up to the black trim on the tank?