Transmetal 2 Megatron????

I totally forgot about this till I was rumaging through the basement and found my TM2 Megs Package. I dont understand why he is considered a TM2. He undewent the same prosess that Primal did, and Primal is not considered a TM2. Also he had three modes like the TM1's.
Im just a little confused can somebody explain?
Im just a little confused can somebody explain?