VLARRSW8 seems to be for your initial return ticket (third letter from last is R for return rather than O for a one way).
Bucket V is a dirt-cheap economy fare bucket. I don't think that you can buy V in one way (VLAROSW8 does not exist).
I don't know your final destination, but the one way K fare is more expensive than the return .

One way to get more information is to suscribe Expert Flyer; you can be a trial member. Then click on "fare information", include your itin and CX and you will see the fares. Then click on the third to last column for your fare.
But this is very complicated as EF only gives the base fare. You would have to reconstruct the various taxes than can be credited for the legs you don't use, as well as the carrier surcharge.
I suggest that you trust us and accept that you are getting a generous refund quote from such a cheap fare.
My personal guess is that CX is giving you a generous 100 to avoid the uncertainty of having you simply no show (and potentially lose the sale of a seat) if they announced 0.refund.