What I mean by my comment is that you are interpreting the word ‘Interchange’ on a printed route map as meaning something specific in the context of the TfL fare structure. That’s your interpretation, which is fine, but it isn’t (as far as I know) TfL’s interpretation. The full map illustrates this with its use of words similar to “a less than 10 minute walking distance”.
The fare structure is/should be what’s published in the fare finder database. That isn’t overridden by what’s printed on maps or what route a passenger actually travels. If mobile Bluetooth tracking ever gets off the ground, that may change. We’re not there yet.
