Jetstar Price in Desktop and Mobile Version

Intent to book a air ticket from Singapore to Malaysia Kuala Lumpur and found there is a price different in normal http://www.jetstar.com/sg/en/home

and http://mobile.jetstart.com/s. Wonder why there is different of $30? Actually there is no different. The mobile version already included all the tax eg airport tax and fuel tax etc while the desktop version only indicate the air ticket price. In the overall price, both of them will be the same.