If you read the TSB notes on nav system upgrades then you'll notice that they are not covered under warranty. If there is a specific reason why the dealer must do it then they will and it will be covered, otherwise it's a request for free labor that is not warranted and so you must pay for it.

Why don't you upgrade the software yourself. Go to the Navigation forum on X5 World and get the latest and greatest one V 29.1

Hope this helps.