Transition to Heavy Lift to Medium is not easy, and autos are different.
Bull ****!
A Helicopter is a Helicopter is a Helicopter.
They are different in different ways....but they are all Helicopters.
Moving from a Chinook to a Single Rotor Helicopter is far easier than going the other direction....as we all learn to fly Helicopters in small Single Rotor Helicopters so we are just going back to what we first learned.
Learning to fully maximize the performance possibilities of the Tandem Rotor takes some effort as it does require some slightly different techniques than the single Rotor.....and sadly some Pilots never learn how to do that.....just as some are at best only mediocre single rotor helicopter pilots.