Could someone please tell me the difference between part number 40100096 vs 40-100-103?

40100096 comes standard with my Rancilio Silvia v3 portafilter. I think it's advertised as triple basket and it's the perfect size when I am dosing 20g. when I am dosing 18g I am afraid there is too much space between the puck and group head. too much space could lead to the top layer being over extracted I think . 40-100-103 is advertised as double basket. I wonder if the double basket is actually shorter? thanks