The following had me thinking. If your Oyster card has a YPRC discount
on it and you wanted to make the most of your generous z2-6 cap,
( £2.80 I think) how would you get charged on the following journey :

Greenford - Camden Road Return ( changing at Shepherd's Bush for
London Overgorund ).

The single fare listed (£2.20) is for travel through zone 1, but if
you avoided zone 1 and travelled within z2-6 as you would using the LO
interchange, would the Greenford-Camden Road and return to Greenford
be capped at £2.80 or would you pay £4.40 ? Is the system designed to
recognise that the above journey ( by touching in / out at Shepherd's
Bush Overground) does not go through z1and hence will allow the
discounted z2-6 cap ?

Rehmat and salamatsys !
:-)