There are factory defaults for the height and distance. In order to go further you will need to get the GUI installed and hook up the quad to your computer to change those settings. The factory default for height is 400'. So it sounds like you were at the limit.
It is short for Graphical User Interface. In this case it is the Yuneec Software you install on your computer in order to commuicate with the Quad. Here is a link to the Yuneec Downloads where you will find the software to install on your computer. Then you will need the Cable that came with your quad to attach the Quad to your computer.
The GUI software is like a diagnostic test to make sure your Q is running properly. You can check for connection issues or motor rotation, etc. You said you got 493'? that's good considering I think the default setting is 300'.
Well the reason it's set to that is because there is a buffer zone of 100 feet between 400 and 500 feet radio control aircraft stay below 400 and real aircraft stay above 500 except in the vicinity of an airport runway or helicopter pad or for water rated aircraft their appropriate landing zone. That's to keep remote controlled aircraft out of real scale aircraft airspace. There are very few place where it is legal to fly radio controlled above 400 feet... I have studied FAA rules for a long time to get my ratings. Trust me. I don't want to hit a real aircraft with my RC or have my real aircraft hit by a model. Thanks