EF Core 2.1.1 I dati dei semi non funzionano con override double

potresti dirmi perché nel mio DB ottengo 0 valori dopo il Seed method ? Ecco come appare:

public static void Seed(this ModelBuilder modelBuilder)
    {
        int countOfWorkers = 10;

        for (int i = 0; i < countOfWorkers; i++)
        {
            modelBuilder.Entity<Driver>().HasData(
            new Driver
            {
                // 10 same workers
                Id = i + 1,
                FarmId = 1,
                FirstName = "name" + i,
                LastName = "lastname" + i,
                UsdPerHour = 7.2,
                HoursPerDay = 8,
                DaysOfWork = 31
            });
        }
    }

E le mie classi di Models :

public abstract class Worker
{
    [Key]
    public int Id { get; set; }

    [ForeignKey("Farm")]
    public int FarmId { get; set; }
    public Farm Farm { get; set; }

    public string FirstName { get; set; }
    public string LastName { get; set; }

    public virtual double UsdPerHour { get; set; }
    public virtual int HoursPerDay { get; set; }
    public virtual int DaysOfWork { get; set; }

    public virtual double CountBaseSalary() => throw new NotImplementedException();
}

public class Driver : Worker
{
    public Driver() => BaseSalary = CountBaseSalary();

    public override double UsdPerHour { get; set; }
    public override int HoursPerDay { get; set; }
    public override int DaysOfWork { get; set; }

    public override double CountBaseSalary() => UsdPerHour* HoursPerDay *DaysOfWork;

}

Sto usando EF Core 2.1.1 . Cosa ho fatto di sbagliato, che ottengo 0's valori 0's per le proprietà su Driver? Se necessario, posso aggiungere ulteriori informazioni.

Il mio DbContext :

public class FarmDbContext : DbContext
{
    public FarmDbContext(DbContextOptions<FarmDbContext> options) : base(options) { }

    public DbSet<Farm> Farms { get; set; }
    public DbSet<Worker> Workers { get; set; }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.Entity<Driver>();
        builder.Seed();
        base.OnModelCreating(builder);
    }
}