usually invoice date and month of sale are almost similar. for brand new cars date of insurance also matters.
0 to 6 months most companies offer 5% to 6%
6 to 12 Months 10%
13 to 24 Months 20%
and so on.
i paid 30% on my car repairs where the car was purchased in FEB 2022 , Althou it is 2 years old, But it falls in the 25 to 36 month category now.