Hi Lauren,
There’s quite a bit to unpick here, so bear with me.
Firstly I’m not quite sure where you get a daily cap of £7.60 from. As Mike suggests above, that is the peak single fare from Old Street to Strawberry Hill changing at Waterloo. The zone 1-5 daily cap is £13.10 which you will be unlikely to reach as I explain below.
Secondly, did you exit and re-enter at Clapham Junction? If you did then there is no need. The Oyster system charges each complete journey, including any changes of train. If you have to exit and re-enter (like at Waterloo) then it will join the two bits together as long as you don’t exceed the interchange time. If you don’t have to leave the station then don’t.
Now to your journey. There are essentially three different routes for charging purposes. Most expensive is Old Street to Strawberry Hill changing between Underground and National Rail at Waterloo (£7.60). Next is Old Street to Strawberry Hill changing at Vauxhall (£6.70). This is because all your National Rail travel is in zones 2-5 and all your Underground travel is in zone 1 so the system charges it as two separate journeys even though it is one. Finally Shoreditch High Street to Strwaberry Hill is £5.70 as long as you don’t touch out at Clapham Junction. This is because the whole journey is treated as National Rail so there is no Underground charge.
Coming home it gets even better. Because your journey starts in zone 5 and ends in zone 1 you are changed off-peak fares during the afternoon peak. This makes both Old Street options £5.40 and the Shorditch option £3.80. There is no benefit to changing at Vauxhall off-peak for this journey.
So, if Shoreditch High Street is as convenient as Old Street for your home then I’d definitely recommend that route for a daily total of £9.50. From Old Street via Waterloo is a daily total of £13.00, so just below the daily cap.
Hope that helps.