"John Salmon" wrote
I have a registered Oyster card with Senior Railcard loaded, so within
zones 1-6, my off-peak daily travel should be capped at £5.00. An
off-peak day return from Upminster to Ockendon with railcard discount,
which I could presumably have bought at Fenchurch Street, costs £2.70 - I
can't see anything indicating that minimum fares or time restrictions
would prevent the use of such a ticket at the weekend.

On a recent Saturday, I made four journeys using Oyster PAYG. The first
two may have been linked by an OSI. I don't think I had any time-out
issues. I started the day with a balance of £14.06 and ended it with
£4.66, so I was charged a total of £9.40. Paper tickets would have cost
£5.00 + £2.70, a total of £7.70. Why was I charged £1.70 more? Is it
anything to do with the anytime day return (undiscounted) from Upminster
to Ockendon being £4.40?

Details, which I don't fully understand (even individually):
Victoria - Tower Hill: In £4.20, out -£2.40, so charge was £1.80.
Fenchurch Street - Ockendon: In £2.40, out -£0.45, so charge was £1.95.
Ockendon - Fenchurch Street: In £5.60, out -£1.70, so charge was £3.90.
Fenchurch Street - Liverpool Street on foot!
Liverpool Street - King's Cross St. Pancras: In £4.20, out -£2.45, so
charge was £1.75.
I am somewhat disappointed to have received only one reply to this message,
so let me try something more general. Is it, or is it not, the case that
Oyster PAYG should always be the cheapest way to pay for a journey within
the area covered by Oyster PAYG? My impression is that Oyster has been
promoted in that way, but now I'm wondering whether that only applies to LO
and LU travel, i.e. excluding other 'National Rail' travel.