Calm down. You are getting worked up over something that you and most of us do not know 100% about since we did not code it. Chances are if the fuel was perfect the user would pont something else out. It’s like apple vs Android but replaced with different flight simulators. Bottom line is we don’t have a flght computer and most elements are estimates until it gets more information such as load, sruise speed, pressure, wind, temperature. Nobody seems to be complaining that your fuel estimation doesn’t look right until you level off.
Don’t let the you tuber get to you. Welcome to the internet.