What is the difference between the John Deere 412R and 612R?

Here is how the John Deere 412R and John Deere 612R compare on John Deere's published specifications:

• Horsepower: John Deere 412R 326 hp vs John Deere 612R 355 hp
• Wheelbase: John Deere 412R 169.3 in. vs John Deere 612R 169.3 in.