There is no doubt contactless, especially offpeak, is substantially cheaper. As commented above, touching in at Liverpool Street Pre 7pm, then out and in at Paddington will ‘fuse’ the journeys. Easily avoided by the use of two cards! In general though, since discovering the offpeak trick 18 months ago I deliberately have a ‘long’ day when I do go up to town (touching in before 6.30am and after 7pm on the return) as it makes the journey much cheaper!
One other thought if you’re not in a desperate rush (or perhaps would like a late night snack) returning home. It’s possible to travel for £3.40 to Hayes. So if you’re ever stuck on an Elizabeth line train, you can hop off, enjoy Hayes town centre, then touch back in on a different card. To twyford, the train fare is £5.50; I suspect it’s similarly cheaper to Reading. Thus generating a subsidy of £2.40 from TfL» to invest in Hayes’ amenities!
You're not the only one that does this - frequently pop in to the Tesco at Hayes on my way home to pick up essentials and save money on my way home to Twyford off-peak. I can get to Hayes from Bond Street for just £2.25 as I have a gold card discount loaded onto my
Oyster▸ . This makes the saving £3.55 and a meal deal is only £3.40 with a Clubcard!
In the morning I frequently touch in at Twyford by 0634 when catching the 0648 train to London and then walk to my office near Bond Street and pay just £8.80! Contactless has really helped reduce the cost of my commute, but surprisingly I don't see many/any others rushing to touch in before 0635 to save.