I've just changed jobs and am still getting to grips with the vagaries of Oyster & the Underground. My question for those of you who know the system better than me is this:

I usually use a combination of either mainline train or Piccadilly plus Northern line to get to and from work, and my OH uses a mainline train and the W&C.

Sometimes after work we meet at Waterloo to get on a mainline train home together but there will be times when we're going out that we'll get onto another line (say, Jubilee) at Waterloo. When that happens, I won't exit at Waterloo and will just change lines on the same journey and be charged accordingly.

However, because there is no way to change from the W&C to the other lines without exiting through the W&C barrier and then entering through the next set of barriers to get to the other lines, would he be charged for two individual journeys or would Oyster recognise that it's a change of lines from W&C to Jubilee and just apply one charge?

Sorry if that sounds confusing or just plain daft but I'd appreciate any answers.

Andrea.