I was poking around Shimano's web site today looking at my brakes (Shimano GRX BR-RX400) and the replacement pads available for them. The resin ones state they are "Resin (5th Generation)", and the number is L05A. The number on the pads I have now is L03A, so I assume that means I have 3rd generation resin pads today. Does anyone know what advantages the newer generations provide?