I commute Hayes,Kent to stratford, changing at Lewisham for the DLR to avoid Zone1. Lewisham / DLR is an OSI and works fine in the morning as even though Hayes-Lewisham is only 2tph all I do is catch “my” train.
Coming back the other way, its not so easy to time it right and if I just miss it I have a 30 minute wait. What happens if I skip the touch out queue at Lewisham DLR and either go through the gateline at lewisham or just run to ladywell and make the non-lewisham service?
If you touch in without having touched out it may well charge you an incomplete journey. You should be able to fill that in, but only up to 3 times a month. It’s also not certain that the system will join the journeys together again automatically. If you head to Ladywell it will definitely be charged as two journeys.
Have you considered getting a zone 2-5 travelcard?
They are zone to zone within zones 1-9, but they still need to know which stations were used. OSIs are only set between certain stations, otherwise the system gets too complicated.