Oh no it's not silly -
RSI is just short for repetitive strain injury
and
TOS is short for thoracic outlet syndrome.

they can be related- my RSI kind of evolved into TOS because I kept being returned to a full duty repetitive job after I mor or less recovered from my acute RSIs. The 10 hr days and speed of assembly production work just kept piling on a little more injury everyday until it became a chronic thing.

Oh that so stinks that they settled with you and now are playing games, just stinks !