Hi,
OK, there are several factors at work here. The biggest is that new fares were uploaded to the system starting from Sunday 8th June. It looks like LNWR have increased some of the daily caps. This seems to be correcting some errors.
The next thing is that it looks like the daily cap was incorrectly set for Leighton Buzzard, so your return journeys were being capped when they probably shouldn’t have been. This explains the cheap afternoon fares which always resulted in a £17.20 daily charge. You have almost certainly gained from this error.
The third thing to note is that the evening peak charging period starts at 1600. As you discovered on Monday, this increases the charge for the trip home. There is a little leeway to allow for clocks being wrong which means that it actually changes over at 1605, but if you want the off-peak fare then you need to touch in at Bank before this time. By touching in in the morning before 0630 you are actually gaining from the pre-peak that TfL operates. You wouldn’t get that with a paper ticket, so you are still winning.
Overall it looks like you were being charged the wrong fares and the wrong caps before this weekend, but you were undoubtedly winning from this error. You still win if you touch in before 0630 in the morning.
