My old man's LG LH-R5500W recorder is not reading the free time available on DVD-RWs properly. An initialized disk is not showing the proper amount of free time on his machine yet on mine its fine.
Try resetting the recorder. Everything digital needs reset somewhere down the line. Try pressing the power on the unit for 10 seconds. If that doesn't work you'll probably have to contact the manufacterer. They all have a certain method for resetting.