Yep... the MPEM is programmed to the new key. The only thing you can do is to buy a "SeaDoo Pro" programmer, and do it yourself. Last time I checked, a personal unit was $399. That will allow you to work on 5 different seadoo's. (5 different VIN/HID numbers)
But, in reference to SeadooBuddy... dealers rarely do it for free. BUT... if you buy the key from them... they normally only charge $15. If you take the key to them, it's $30 to $60 to have it done.