Extending Extended Warranty

Has anyone extended their extended warranty? I'm wondering how they do it. Do they void the original contract and initiate a new one or do they just add on the additional time/miles to the original contract? The reason I ask is I have the Platinum plan and it looks like I may need to extend the miles to cover the time until the car's paid off. My concern is there appear to have been changes to the terms of the coverage since I bought my plan and there may be more before I'm sure I need the extra miles. This is why I would like to know if the extension continues under the original terms or the new ones? If the terms change do they change immediately or at the end of the original contract period.

 

Thanks for the suggestion. If I decide to keep her longer than 100K I will consider that. What I'm interested in though is extending the Platinum plan I have. I financed for four years and bought the 4 year/65 K mile plan. It's starting to look like I may exceed the mileage before the four years are up. In June I will have had the car for one full year and will be better able to judge if I'm going to need to extend the warranty further.

 

Thank you for the feedback. I was told when puchasing my 4yr/36,000 mi. Platinum plan I could purchase additional time/miles at any point before the car reached 3yrs or 36,000 miles. I just wondered if anyone else had done this and if so what was the cost and how did it affect the terms of the contract?