The weekend and weekday tickets may have the same name, but they are ccompletely different tickets behind the scenes (ticket types WTC for weekend, and AM3 for weekday).
Your Super Off-Peak Day Travelcard used to be one ticket for weekend and weekday use before March 2025, but Southern (likely as a result of the DfT wanting them to spend less of taxpayers' money in subsidy -- so much for simplification) decided that was too cheap for travel on a weekend, and introduced new weekday-only and weekend-only versions of the Travelcards for use from 2 March 2025.
This affected a large number of stations in the south.
For your journeys, you could save £1.85 (or £5.70 if you don't mind using Thameslink from Haywards Heath into London) if you instead buy:
You'd change between the two tickets at Haywards Heath as both are valid at this station.
You'd also gain the ability to travel from Lewes to Brighton and then to London (or the same in reverse) with this combination of tickets, provided the train stops at Burgess Hill (where you'd switch between the tickets in this case).