SFS pay structure is an hourly base pay based on your city with reward pay of £1 per drop:
London: £9 per hour
Rest of UK: £8 per hour
For example, in London, if you complete a 3-hour slot, and did 5 deliveries, you will earn £9 x 3 = £27 in base pay + £1 x 5 = £5, total earnings = £27 + £5 = £32.
The earnings you will see in app are not relevant and the above is the pay you will receive on your SFS payment statement. The SFS Payment Statement is a separate statement. If you also do deliveries in the shared fleet you will receive one regular statement and one for SFS!