Recliner wrote
....
"Michael R N Dolbear" wrote

Kings Cross has always been a OSI (Out of station interchange), as
discussed here, with from 15 to 40 minutes allowed to pass another
gateline as part of the same journey. So with a "13 min turnaround"
it
seems likely that you were trapped by the maximum journey time rule
and charged for two incomplete journeys

Wouldn't simply returning to the original station have the same
effect?
But, if Paul had returned to a station one stop away, within the now
very complicated maximum time rules, he might have had a bargain
instead.

Not sure, lacking experimental data, but provided you took at least 15
minutes I thought you were just charged for a 1 zone excepyt that if
the OSI made it a continuous journey the logic for the pink route
validators may have noted a journey via zone 1, hee !

Various people have done a touch in/out just to collect, variously, a
online top-up, set up auto top-up or go home to collect something so
maybe the 15 minutes is for the second entry as an anti-passback
measure ?

--
Mike D