Glad to see the usual mess applies to the fares to Okehampton.
I looked up fares from Pershore on brfares.com and found that there is a via Worcester fare. Off peak return £44.90 with Senior railcard. Its not clear if this means Via Worcestershire parkway as well.
However even when the National rail enquiries journey planner gives me a journey via Worcester Shrub hill the fare given is the not London fare. £64.60.
"Via Worcester" will be via the Worcester group: both town stations (plus Droitwich Spa in theory; I don't think you can use it in practice). WOP has not been added to the group, which is one of the routeing points for WOP, the others being Cheltenham Spa, Oxford, and Bromsgrove.
The issue is why that via Worcester fare is not found, even for a journey via Worcester. At first sight it looks as if it might a lack of adjustments to allow for OKE, or WOP, or both, as new stations. But the failure to route with a change at WOP is more likely to be just a matter of connection times, and the same missing fare happens if you are only going to Exeter. From Worcester, you do get offered the change at WOP, as well as going to Cheltenham to change (onto the same train). That looks odd, but is simply due to the nearly 1 hour wait from the former being enough to offset the extra change. I suspect that
XC▸ have not defined that fare correctly in some way.
Leaving aside the overall level of fares set by XC, there are other oddities that suggest they don't look very closely at what they are doing. One I spotted is for Worcester-Exeter, where XC set the only two fares. One is routed "via Bristol", and an anytime single is £120.10 - high even by XC's standards. The other is routed "not via Birmingham", and that SOS is £64.80, and that is the only fare found by the
OJP▸ . Is there any practical route avoiding Bristol for the other fare to apply to? Common sense says no, and the Routeing guide (for once) agrees. Mind you for Cheltenham-Bristol
GWR▸ set the only fare, and it's very much cheaper, so splitting undercuts both of these.