I'm not sure about break-in other than that tire wear/fuel consumption needs to be on. But unless something has changed, cars do not get mileage added to them when driving in free run, or in a race with only one car. I used to do both alone in my lounge, thousands of miles worth, and never did it affect the miles driven at all.
If break-in can occur in that situation it makes things that much more confusing for people keeping track, since you can already add miles to the car without breaking it in or wearing it out during the seasonal time trials.