It’s the meter that sets the times, not anything connected after it. You then have a separate timer to switch things on during the cheap times. How this is set up really depends on how the property is wired up. All the heating might be on one circuit, so you’d have one timer set to the right times. Sounds like what you’ve got and there’s no reason why you can’t set it up how you like, including using non-E10 hours if it gets cold.