If I had to guess, I’d suggest it was because Ewell West is subject to a normal Oyster Zonal fare (z4-6) so will be standardised at the Oyster rate while the Epsom fare is probably set by SWR and won’t be related to oyster rates at as it’s outside the zones.
This reply was modified 3 months, 3 weeks ago by Feathers.
I’d agree with Feathers. Fares on late adopting NR services within zones 1-6 are set by representatives of the TOCs concerned under the umbrella of ATOC (now RDG). This group will include SWR, but I don’t think the people setting fares from Epsom will particularly have thought about the fares within the zones.
You could write to SWR and ask them if they have any comment.