That is soooo not true. You may obtain your turbine waiver without having to buddy box with anyone. In fact, you don't even have to fly a jet for the demonstration flights! You can fly, to quote the AMA, "The qualification flight will be performed with a model capable of sustained speeds of 100MPH or higher". That can be any fast prop plane that you have flown at least 50 times prior to your qualification/demonstration flight.

Having said that, the only mention of buddy boxing is in order to fly a turbine jet before you fly the turbine qualification flight with a turbine powered jet. There is no mention of 5 flights before you get the waiver. In fact the AMA says the number of buddy box flights before the "instructor" releases you for your demonstration flight (again, only applicable if you are determined to do your qual flight with a turbine jet) is at the instructor's discretion. Could be two flights or it could be 20.

The only mention of 5 flights is a requirement that your first 5 solo flights (with a turbine powered jet) "shall be supervised by an experienced turbine pilot". There is no mention of buddy boxing for these first 5 solo flights.

So, my advice to you is not to make this process harder for you than what is necessary. Do your demonstration flight with a fast prop plane.

To verify my comments made above, go here and have a good look at the lower part of page three and all of page 4:

http://www.modelaircraft.org/PDF-files/510-A.pdf