There are two separate 'rules' mentioned in that last paragraph. One about excessing Off Peak/Super Off Peak and another about upgrading to 1st Class.
The final sentence says 'this rule' and not 'these rules' so must refer to the preceding rule about 1st Class. It can't possibly be referring to the rule about excessing Off Peak/Super Off Peak as Penalty Fares should not be issued in circumstances where a ticket is not valid merely because of a time restriction.
From the
(Strategic Rail Authority - about)%20-%20Penalty%20Fare%20Rules%202002.pdf#page=12" target="_blank">Penalty Fares Rules:
7 Circumstances in which a penalty fare may not be charged
7.6 An authorised collector must not charge a penalty fare to a person whose ticket is not valid only because of a published restriction, as described in condition 12 of the National Rail Conditions of Carriage.
Besides which, the earlier text of condition 12 from the
NRCoC▸ is quite clear in mentioning if,
the ticket you are using is not valid for the train you are travelling in, then:
(a) you will be liable to pay an excess fare (the difference between the price paid for the ticket you hold and the price of the lowest priced ticket available for immediate travel that would have entitled you to travel in that train for the journey shown on the ticket)
Note that bit about
'the train you are travelling in'
.
"This rule does not apply"...I read that as the whole rule/paragraph, so your upgrade too.
I don't. For the reasons given. Also changing a Super Off Peak/Off Peak to an Off Peak/Anytime is an excess not an upgrade.
As for what barrier staff say, they shouldn't overrule the National Rail Conditions of Carriage but can and do make things up as they go along. So yes, if there's time, and for an easy life, purchase your excess before boarding.