Ah thanks for that - particularly with the lack of excessing in the first place!
Let's assume for a moment that the 'Route Birmingham' ticket can actually be excessed to the 'Route WSMR Trains only', to make sure I've understood the excess distribution.
You're on board, and ask for an excess - let's also say the excess costs more than £0.00 for simplicity's sake, and it costs £10.00.
WSMR charge £10.00 to the customer, which presumably goes to their accounts office every so often. Step 2, by the very nature of the TOC specific ticket, implies that WSMR would get 100% (i.e. the whole £10.00) as they could be the only carrying operator for the ticket. (Incidentally, is this step similar in idea to how ORCATS distribution works? An excess available for use on more than one operator has the same/similar distribution percentages? Or would 100% go to the operator of the service if issued on-board and, as such, allocations are different for each individual excess (even if between the same locations)? I'm assuming the former as it makes things a lot easier in the scheme of things!).
It would seem step 3 is combining steps 1 and 2. The allocation percentage multiplied by the amount of the excess. So, in this hypothetical example WSMR would receive £10.00.
Based on this, because the excess in my above example (if it were to exist) was £0.00, WSMR would get £0.00 and still all of the Route Birmingham allocation would go to Virgin (or maybe including Chiltern and/or London Midland in small percentages too)?
I can see now why even if the excess is possible they would not issue it, sooner wishing you to purchase a new ticket they'd actually get revenue from!
Based on your last paragraph it would seem it's in a TOC's best interests to ensure they have an allocation for every flow they could accept excesses on, otherwise they'd get nothing at all... Interesting!
Let me go through another (more real!) example to make sure I've grasped things properly.
I hold a London Terminals to Southampton Central Route Hassocks/Horsham Off Peak Return. I wish to travel with SWT and excess the ticket to an Any Permitted.
Originally I'll assume that most (if not all) of the original £28.00 would go to Southern.
The nice guard on the train takes my £7.20. End of their shift it gets cashed up and soon enough finds itself in SWT Accounts.
SWT have a percentage allocation for this that determines how much of the £7.20 they can take - presumably all of it in this case.
Now I think about it and how greedy of SN this would be and unfair on SWT - I'm assuming that the percentages are not confined to a 0-100% range? The vast majority of the £35.20 Any Permitted SVR would go to SWT if I was to buy that ticket in the first place! For them to only get £7.20 out of an excess would seem wrong.
This would then presumably allow the full £35.20 to be distributed as it normally would (so the percentage allocations would have to be different from ORCATS and also have to change every Fares Period so as to distribute revenue correctly)? Or have I gone completely weird with my reasoning?
You're right - very complicated indeed!
--- old post above --- --- new post below ---
I think we're all agreed that if WSMR are excessing then the correct excess would be £5.75
Ahhhh of course!!! I've rather stupidly been getting hung up with the WSMR Trains Only route and forgetting all about 'Any Permitted' even existing!!
On that note, it's about time my overworked, confused brain was given a rest!