Sea Dweller question...

[Soccerlaw]

I'm going to apologize in advance for my lack of knowledge that I am sure will be evident in this post... I have a 15yr old Sea Dweller and the diver's extension piece has just snapped (the two metal tabs that connect the extension to the link snapped off). The person servicing my watch has offered to get a replacement part from a colleague for $200 but it seems like there are several of the "L" version from the tool kit available for around $50-$75. Is there a huge difference between the "L" and the "S" version that I believe comes on the watch? I've actually never used the divers extension (usually when I dive I'm only wearing a spring suit) so unless there's something I am missing I can't see there being any functional difference for me between the two. Any expert advice would be greatly appreciated as I am a complete novice in this area and this site seems to be a full of tremendous resources.