Many thanks for the clear explanation, Mike. The gap in my knowledge was that the off-peak cap didn’t start until the first off-peak journey. Previously I’d assumed that the day started with the first journey and charges were then allocated to whichever cap was applicable at the time of touch-in during the day.
It makes sense that the system works the way it does – even though it makes things more complicated – but because I make so few peak journeys it hadn’t ocurred to me that it worked that way. Thanks again.